A Derecho Pet Safety Plan: Which Alert Reaches Your Phone, and the Wind Speed at Which It Does Not

There is a version of this storm that circulates as a warning-free monster: a wall of wind that appears out of a clear afternoon, with no siren, no forecast, and nothing on a map. It is a good story and it is not what NOAA publishes. The Storm Prediction Center’s own FAQ page answers the question in one sentence: “Derechos rarely occur without warning, although warning lead times may be comparatively limited during the early stages of storm development.”

The real problem is narrower, more specific, and considerably more useful to a household with animals in a yard. The alert does arrive. It arrives as a Severe Thunderstorm Warning. And since August 2, 2021, only one of the three tiers of that warning pushes an alert to a phone, at a wind speed higher than the one that defines the storm class in the first place.

That is the gap this page is about. NOAA defines a derecho at 58 mph along the length of the damage swath. The Wireless Emergency Alert attached to the weather service’s own warning fires at 80 mph. Between those two numbers sits a stretch of a genuine, 250-mile derecho path where a warning is in effect, the wind is doing damage, and no federal weather alert reaches your handset. Your county still can send one, which is a separate point covered below.

This page decodes that. What the current NOAA definition actually says and what changed in 2025. Which alert reaches you and at what threshold it does not. What the hurricane playbook gives a pet owner that this hazard cannot. And the one thing that is genuinely new for an animal household: what a line moving at highway speed does to the window in which you can still get a cat into a carrier.

What this page does not do is re-decide questions the rest of this site has already worked through. Whether to crate or leave loose, how to get a large dog down a flight of stairs, what to do when the structure you live in is a manufactured home, and how to survive a week without power are each handled properly elsewhere, and this page routes you there rather than publishing a second, thinner answer.

What NOAA Actually Calls a Derecho, and What Changed in 2025

Start with the definition, because a great deal of writing about this hazard uses numbers that are not NOAA’s.

The Storm Prediction Center’s Derecho Facts page, which self-dates as last updated April 28, 2026 and which we read on August 15, 2026, states it in one sentence:

“By definition, if the swath of wind damage extends at least 250 miles (about 400 kilometers) long, includes wind gusts of at least 58 mph (93 km/h) along its length, with several, well-separated 75 mph (121 km/h) or greater gusts, and originates from an MCS that moves faster than the mean wind speed (thus being primarily cold pool driven), the event may be classified as a derecho.”

Four things in that sentence matter to a household rather than to a meteorologist.

250 miles, not 100. The qualifying swath is long. That is why a derecho is a regional event rather than a neighborhood one, and it is why the aftermath section further down matters more than it does for a tornado: the damage, the outage and the closed gas stations are all spread across the same 250-plus miles.

58 mph is the floor, and it is a floor for the whole length. That number is going to come back. Hold onto it.

75 mph or greater gusts, several of them, well separated. The strong wind is not continuous along the path. It comes in patches.

It moves faster than the mean wind. That clause is doing the work in the timing section below. This is a system that outruns the air it is embedded in.

The same page adds the radar signature: the system “also should contain certain radar-observed storm features such as bow echoes and rear-inflow jets”. And it dates its own definition: “These requirements were added in revisions to the definition of “derecho” introduced in 2016 and 2025, with the intention of making the definition more physically-based and phenomenally distinct — ie., focused on the meteorological processes believed responsible for the production of organized, damaging surface winds.“ We are reproducing that sentence’s three-hyphen dash and its “ie.” exactly as the page writes them.

The page also flags its own incompleteness, which is worth quoting because it changes how much weight to put on the rest of it:

“The definition of a derecho was recently modified, based on recent research (Squitieri et al. 2025a, b), with the definition updates reflected in the “Definition of a Derecho” section below, and on the derecho FAQ page. Work is underway to modify our “About Derechos” webpage, as well as create a comprehensive archive on derechos based on the modified definition, which we hope to have available soon.”

So the Storm Prediction Center is telling readers that sections of that page below the definition may not yet reflect the 2025 revision. Everything quoted from those lower sections on this page is attributed to the page as we read it, on August 15, 2026, rather than presented as the settled current science.

Three Documents, Four Numbers: Where the Definitions Diverge

Here is the part most writing on this hazard gets wrong by accident. NOAA publishes the derecho definition in more than one place, the wordings are not identical, and a peer-reviewed paper the Storm Prediction Center itself cites uses a third set of figures in different units. Welding them into one sentence would produce a definition nobody published.

So they go in a table, one row per document, with “not addressed” where a document is silent. Every cell is that document’s own wording, read August 15, 2026.

Document	Swath length	Wind along the length	Strongest gusts required	Width of the parent system	What kind of document this is
SPC, Derecho Facts page	“at least 250 miles (about 400 kilometers) long”	“wind gusts of at least 58 mph (93 km/h) along its length”	“several, well-separated 75 mph (121 km/h) or greater gusts”	Not addressed	The Storm Prediction Center’s public definition page, self-dated Last updated Apr 28, 2026
SPC, Derechos FAQ page	“must extend either continuously or intermittently more than 250 miles (about 400 km)”	“at least 58 mph (50 knots or 93 km/h) or greater along most of its length”	Not addressed as a count; the page instead states that winds “typically are less than 100 mph” and that “gusts as high as 130 mph have been recorded”	“originate from an MCS with a line-width of at least 60 miles (about 100 km)”	The Storm Prediction Center’s plain-language FAQ page
Squitieri, Wade and Jirak, BAMS 106(1)	“pathlengths of at least 400 km”	Not addressed as an mph floor	“at least five reports of 33+ m s−1 wind gusts, separated by 80 km”, of which at least three must be measured rather than estimated	Not addressed	A proposed definition in a peer-reviewed journal article, not an SPC product

Three differences in that table are worth naming out loud, because each one is a trap.

The two SPC pages phrase the same criterion differently. The Facts page says the gusts run “along its length” and the FAQ page says “along most of its length”. Neither is wrong. They are two registers of one idea, and quoting one of them while citing the other is how a small error gets a NOAA byline.

The 60-mile width criterion exists only on the FAQ page. The Facts page’s definition sentence does not carry it. If you need that criterion, cite the FAQ.

The journal paper is a proposal, and its units are different. The paper’s abstract states: “we propose that the term derecho be used for thunderstorm wind swaths that have pathlengths of at least 400 km, with no more than 1-h or 200-km (temporal or spatial, respectively) gaps allowed between wind reports, with at least five reports of 33+ m s−1 wind gusts, separated by 80 km, required for derecho identification.” It adds: “To account for possible overestimation of wind speeds, at least three 33+ m s−1 thunderstorm wind gust reports, separated by 80 km, need to be measured.” And it describes its own novelty as diverging from earlier work “by explicitly requiring several hurricane-force (33+ m s−1) gusts and restricting derecho wind swaths to cold-pool-driven MCSs.” Hurricane force is a higher bar than the 75 mph the Facts page publishes. The paper says so about itself. It is the research behind the revision, not the operational definition, and the Storm Prediction Center’s own public page is the operative statement for anyone who is not writing a paper.

The Wind Is Not the Same Everywhere Along the Path

This is the single most useful thing on the Derecho Facts page for someone deciding whether their address is in trouble, and it is easy to skim past.

“The winds associated with derechos are not constant and may vary considerably along the derecho path, sometimes being below severe limits (57 mph or less), and sometimes being very strong (from 75 mph to greater than 100 mph). This is because the swaths of stronger winds within the general path of a derecho are produced by what are called downbursts, and downbursts often occur in irregularly-arranged clusters, along with embedded microbursts and burst swaths.”

The page then gives the mental image: derechos “might be said to be made up of families of downburst clusters that extend, by definition, continuously or nearly continuously for at least 250 miles (about 400 km).”

A family of downburst clusters, not a uniform wall. Which means being inside the derecho tells you very little about the wind speed at your own fence line, and it is the physical reason the alert tiering in the next section behaves the way it does.

The FAQ page adds the ceiling: “While derecho winds typically are less than 100 mph, gusts as high as 130 mph have been recorded — equivalent to those with strong EF2 tornadoes.”

The Alert Does Arrive. Here Is Which One, and What It Says.

The product is a Severe Thunderstorm Warning. This site already decodes the watch-and-warning posture split, quoting the National Weather Service’s own language, on our page about what to do with a pet when the shaking or the sky turns, and there is no reason to re-argue it here. That page carries the two postures, Be Prepared and Take Action, and it already carries the watch-area sentence repeated below, so treat the repetition as a deliberate quotation of a shared source rather than a second answer. What that page does not carry, and what a derecho reader needs, is the matching sentence about how small a warning area is, and the shelter instruction attached to the warning.

On geography, the National Weather Service’s watch-versus-warning page states that a watch area is “typically large, covering numerous counties or even states”, while warnings “typically encompass a much smaller area (around the size of a city or small county) that may be impacted by a large hail or damaging wind identified by an NWS forecaster on radar or by a trained spotter/law enforcement who is watching the storm.”

On shelter, the same page’s warning entry reads: “Severe Thunderstorm Warning: Take Action! Severe weather has been reported by spotters or indicated by radar. Warnings indicate imminent danger to life and property. Take shelter in a substantial building. Get out of mobile homes that can blow over in high winds.”

Read that last pair of sentences carefully, because it settles something. Take shelter in a substantial building. Get out of mobile homes. That is the same instruction our mobile home tornado page already gives for the tornado case, although it gets there through different documents: that page is built on the Storm Prediction Center’s tornado safety page, the National Weather Service’s national tornado safety page and FEMA’s protective-actions card, none of which is the severe thunderstorm page quoted here. Different hazard, different sources, same instruction to leave a manufactured home for a sturdy permanent one. The tornado sheltering playbook does not fail for a derecho. It transfers. What fails is something else entirely, and it is the subject of a later section.

The National Weather Service also names pets for this hazard directly, which is worth flagging because agency pet lines are rare enough that people assume they do not exist. Its page on what to do during severe weather, read August 15, 2026, states:

“At Your House: Go to your secure location if you hear a severe thunderstorm warning. Damaging wind or large hail may be approaching. Take your pets with you if time allows.”

If time allows. That qualifier is inside the federal instruction, not appended to it here, and it is the same qualifier the National Weather Service attaches to its tornado guidance. It ranks your own life above the retrieval, and no part of this page argues with it.

The Three Tiers, and the One That Rings

Since August 2, 2021, a Severe Thunderstorm Warning is categorised by damage threat, with a tag attached above the lowest tier and no tag at all on the default one. The National Weather Service announced it in a news item dated July 22, 2021, and named this exact hazard class in the first paragraph:

“Severe thunderstorms can be life-threatening, but not all severe storms are the same. Hazardous conditions range from tornadoes, large hail storms, and widespread straight-line winds called derechoes, to cloud-to-ground lightning and flash flooding.”

The tiers, and what each one does to a phone, come from a National Weather Service graphic on the damage threat categories, published through its Chicago forecast office. The table below is that document’s own content, with its own wording preserved.

Damage threat tag	Wind	Hail diameter	Wireless Emergency Alert?
“Base (no tag; default)”	“58 mph (60 mph will appear in the warning)”	“1.00 inch (U.S. quarter)”	“NO”
“Considerable”	“70 mph”	“1.75 inch (golfball)”	“NO”
“Destructive”	“80 mph”	“2.75 inch (baseball)”	“YES”

That document adds two rules that matter. First: “The highest of the categories will be invoked from either a qualifying wind or hail value, or both.” So a storm can reach the destructive tier on hail alone, with wind well below 80 mph. Second: “Wireless Emergency Alert (WEA) messages will be activated on mobile devices whenever a Severe Thunderstorm Warning with a ‘Destructive’ tag is issued or updated.”

The July 2021 news item gives the same thresholds in prose and adds the frequency figure: “On average, only 10 percent of all severe thunderstorms reach the destructive category each year, nationwide. Most of these storms are damaging wind events such as derechoes and some of the larger, more intense thunderstorms, called “Supercell” storms that can typically produce very large hail in their path.”

Ten percent. That is the share of severe thunderstorms that reach the tier that rings a phone.

The Exact Words on the Screen

The National Weather Service published proposed text for these alerts, which is the closest thing available to knowing what you will actually be looking at. Public Information Statement 21-28, issued 920 AM EDT Mon May 3 2021, requested feedback on the wording until June 2, 2021. These are its samples, and they are samples in a feedback request rather than a transcript of any live alert. The times in them are placeholders.

The 90-character English message:

“NWS:DESTRUCTIVE WIND STORM in this area til 1215PM TZDT. Take shelter now. Check media.”

The 360-character English message:

“National Weather Service: SEVERE THUNDERSTORM WARNING in effect for this area until 12:15 PM TZDT for DESTRUCTIVE 80 mph winds. Take shelter in a sturdy building, away from windows. Flying debris may be deadly to those caught without shelter.”

The same statement published Spanish versions. The 90-character Spanish message reads “SNM:TORMENTA DE VIENTO DESTRUCTIVA en esta area hasta las 1215PM TZDT. Tome refugio ahora.” If anyone in your household relies on Spanish-language alerting, our bilingual pet emergency care instructions page covers the wider problem of a caregiver who reads a different language than the person who wrote the instructions.

One detail from that statement changes how you should read a short alert. On phones limited to 90 characters, the messages “will not contain the wind speed nor hail size.” A shorter alert is a phone limitation, not a smaller storm.

Finally, the master list. The National Weather Service’s Weather-Ready Nation page on Wireless Emergency Alerts answers which of its warnings send one, and reads: “Warnings for Tsunamis (see Fact Sheet), Tornado, Severe Thunderstorm (only when the damage threat is destructive), Flash Flood (only when the damage threat is considerable or catastrophic), Hurricane, Typhoon, Storm Surge, Extreme Wind, Dust Storm and Snow Squall.” We read that page on August 15, 2026 and the fragment “Severe Thunderstorm (only when the damage threat is destructive)” is word for word what our inland hurricane preparedness page recorded from the same page on August 5, 2026. Two pages on this site, one source, one wording.

Read one question further up that page than the list, because the next section of this page depends on it. Asked what a Wireless Emergency Alert is, the same page answers that they are “emergency messages sent by authorized government alerting authorities through your mobile carrier” and that “Government partners include local and state public safety agencies, FEMA, the FCC, the Department of Homeland Security, and the National Weather Service.” Asked what types of alert you will receive, it lists “Extreme Weather and Hydrologic Warnings”, “Local emergencies requiring evacuation or immediate action”, AMBER Alerts, Blue Alerts and Presidential Alerts. The list quoted above is the National Weather Service’s own share of that system, not the whole of it. Our inland hurricane page draws the same distinction from the same page, and this one holds to it: everything below about a threshold that does not ring is about the weather service’s warnings, and a local agency remains free to alert you on its own authority.

The Gap This Page Exists For

Now put the two halves together, and be honest about who is doing the putting.

What the sources say. The Storm Prediction Center defines a derecho as a damage swath with gusts of “at least 58 mph (93 km/h) along its length, with several, well-separated 75 mph (121 km/h) or greater gusts”. The National Weather Service’s damage threat table lists the Wireless Emergency Alert column as NO at the 58 mph base tier, NO at the 70 mph considerable tier, and YES at the 80 mph destructive tier. The Storm Prediction Center separately states that derecho winds “may vary considerably along the derecho path, sometimes being below severe limits (57 mph or less), and sometimes being very strong (from 75 mph to greater than 100 mph).”

What the sources do not cover. Neither document, and nothing else we opened on August 15, 2026, states the consequence of holding those two number sets side by side, or says anything about what the tiering means for somebody standing inside a derecho path with animals in a yard.

What this site concludes. This is our reasoning, not NOAA’s. The wind speed that makes an event a derecho is lower than the wind speed that fires a phone alert from the weather service’s own warning. Because the wind varies along the path, and because the tag is set on the warning for a particular polygon rather than on the storm as a whole, a household can be inside a genuine, 250-mile-plus derecho, under a valid Severe Thunderstorm Warning, in a wind that will take down a tree, and receive no National Weather Service alert on a handset, because that stretch was warned at considerable or at base. Treat that alert as a floor rather than a trigger. If you wait for the buzz to bring the animals in, you have chosen a threshold higher than the one that defines the hazard.

Say precisely what that conclusion does and does not cover, because the boundary is the difference between a useful warning and a false one. It is a limit on the National Weather Service’s own warning products. It is not a claim that your phone cannot ring. The same Wireless Emergency Alerts page quoted above states that these messages are “emergency messages sent by authorized government alerting authorities through your mobile carrier” and that “Government partners include local and state public safety agencies, FEMA, the FCC, the Department of Homeland Security, and the National Weather Service.” Its list of what you may receive includes “Local emergencies requiring evacuation or immediate action” alongside the weather warnings. So a county or state emergency management agency can push a Wireless Emergency Alert of its own in a situation the destructive tag does not cover. Our inland hurricane page reads that same page the same way, from the read it made on August 5, 2026. What no reader can rely on is that this will happen for a 70 mph stretch of a derecho, because whether it does is a decision made by a local agency, not a threshold published in a table.

Two consequences follow from that, and both are actionable today rather than during a storm.

Keep a second path that does not depend on the destructive tag. The National Weather Service states that all Severe Thunderstorm Warnings continue to be issued and distributed “via weather.gov, NOAA Weather Radio, Emergency Alert System and through dissemination systems to our emergency managers and partners.” A NOAA Weather Radio receiver with a tone alarm does not care what tag the warning carries. Our inland hurricane page works through the NOAA Weather Radio option in detail, including what it depends on and where it fails, and our wildfire alert apps page covers the county-level opt-in notification systems, which are a separate sign-up from Wireless Emergency Alerts even though the same local agencies can also issue a Wireless Emergency Alert.

Act on the watch. The watch is the stage that is reliably ahead of the line. More on why in the timing section.

Sirens Are a County Question, and an Outdoor One

The claim that a derecho arrives with no siren is one of the two most common things written about this hazard, and it does not survive contact with county emergency management agencies. It also does not invert into “sirens will sound”, because siren policy is genuinely local. Three agencies were read on August 15, 2026. All three sound sirens for a Severe Thunderstorm Warning at an 80 mph threshold, and each states its trigger slightly differently.

Agency (read 2026-08-15)	Severe thunderstorm siren trigger, in its own words	What it says about indoor audibility	Coverage limit it publishes
Dane County, Wisconsin Emergency Management	Sirens “will also sound for areas impacted by Severe Thunderstorm Warnings issued by the National Weather Service that carry a “destructive” tag. This tag is associated with strong thunderstorms with reports of 2.75-inch diameter (baseball-sized) hail and/or 80 mph winds.“	Sirens “should not be relied upon to be heard inside a structure”; “If you are sleeping, an outdoor siren will probably not wake you up.”	No statement that the network leaves parts of the county uncovered; the page states there are “144 outdoor warning sirens in the Dane County system” and that they are “located in the most densely populated areas of the County”
Knox County, Indiana Emergency Management Agency	“Outdoor Sirens will be activated for a Severe Thunderstorm Warning with a “DESTRUCTIVE” damage threat tag indicating 80 mph winds and/or hail of 2.75 inches or greater.”	“It is important that citizens never rely on these sirens as a source of warning while indoors, even if a siren is nearby and easily heard indoors. These sirens are only meant for and designed to alert people who are outdoors and away from other sources of warning methods.”	No site count published; the page instead explains that activation follows the warning polygon, and that sirens can be sounded “all at once, by zone (North, Central, South), or individually”
Cherokee County, Georgia Emergency Management Agency	Sirens sound when “A Severe Thunderstorm Warning is issued and within the text of the warning, winds are forecast to be greater than 80 MPH.”	“Most homes and buildings are designed to keep sounds out, thus outdoor warning sirens are most useful for alerting people who are outside their home, in parks, or shopping areas.”	“Cherokee County only has 58 siren sites; they do not cover the entire county.”

Cherokee County publishes the sentence that scopes the entire question, and it belongs in front of every siren claim anyone makes: “Warning siren policies vary from county to county.”

Three counties are a demonstration, not a national rule. What those three do establish is that “no siren sounds for a derecho” is false as a general statement, and what Cherokee’s sentence establishes is that “sirens will sound” is equally unsafe to publish as a general statement. The honest output is an action item rather than a fact: call your own county or parish emergency management agency and ask what triggers your sirens.

Two further points from those pages matter more to a pet household than the trigger does.

Sirens are an outdoor system, and all three agencies say so. Dane County is blunt about it, in capitals: “NO! The sirens are the OUTDOOR component of the warning system. The siren system is not designed to alert people who are indoors.” Knox County states it as an instruction rather than a description: “It is important that citizens never rely on these sirens as a source of warning while indoors, even if a siren is nearby and easily heard indoors.” Cherokee County gives the reason: “Most homes and buildings are designed to keep sounds out, thus outdoor warning sirens are most useful for alerting people who are outside their home, in parks, or shopping areas.” On the sleeping household specifically, Dane County writes: “If you are sleeping, an outdoor siren will probably not wake you up.” The word probably is the agency’s. For a plan that depends on being woken up to bring animals in, that is disqualifying on its own.

Silence afterward is not an all clear. Cherokee County says it without tying it to any one product: “When the sirens stop it does not mean the danger is over. There is also only one tone that will be sounded. There will be no “all clear” signal provided by the sirens.“ Knox County states it as a warning: “It is important to remember that a siren turning off does NOT indicate that a threat is over.” Dane County publishes the same rule, and its wording is worth reading for its scope rather than borrowed for this hazard: it appears in a paragraph written about a Tornado Warning activation, where the sirens “will only sound once, at the onset of the warning, and no ‘all clear’ signal will be sent.” Dane’s page does not say whether the once-only pattern also governs its severe thunderstorm activations, so we do not extend it. Cherokee’s and Knox’s sentences are unscoped, and they are the ones to act on. If you were planning to let animals back into a yard when the noise stops, those are the sentences that should stop you.

Why the Warning Is a Polygon, Not a County

Knox County publishes the clearest plain-language explanation of the geometry, and it matters here because the tiering above is applied per warning:

“Severe Thunderstorm Warnings and Tornado Warnings are not issued based on whole counties. When the National Weather Service issues a Warning, the meteorologist will “draw” an area known as a polygon on their workstation for the affected areas. This polygon represents the actual Warning area. If you are inside the warning polygon, you should go to a safe location and monitor updates.”

That is reproduced with the county’s own curly quotation marks around the word draw. The practical consequence for anyone tracking this: your county being “in the warning” and your address being inside the polygon are different questions, and the second one is the one that decides whether an alert reaches your handset.

What the Hurricane Playbook Gives You That This One Cannot

Here is where the genuine failure lives, and it is not the tornado playbook.

A hurricane pet plan is a calendar. Our T-minus storm countdown card exists because a tropical system hands a household hours to count backward from, and every hour figure on that card is traced to the county or agency that publishes it. Boarding calls, prescription refills, fuel, a hauling decision for large animals, a drive to a relative’s house: all of it hangs off a lead time that a named forecast product supplies days out.

A derecho supplies nothing of the kind, and the difference is worth being precise about rather than sweeping.

What we could not find is a track-and-cone graphic for an individual convective system. We read the Storm Prediction Center’s own description of its convective outlook products on August 15, 2026. What it describes is probabilistic and categorical area forecasts, not a forecast track for one storm complex with an uncertainty cone drawn around it. That is a statement about the product descriptions we opened, not a claim that nothing anywhere resembles one.

There is no pre-drawn evacuation zone to look up, in the sense a coastal reader means it. Our evacuation levels decoded page covers the lettered hurricane zones and the Level 1/2/3 ladders that exist for other hazards. Nothing in the severe-thunderstorm product suite we read is that.

And therefore there is no boarding deadline. A kennel drop-off time computed from a landfall forecast has nothing to be computed from here.

But Something Absolutely Does Map It

This is where the “nothing on a map” version of the story falls apart, and where a pet household gets its actual planning tool.

The Storm Prediction Center publishes convective outlooks for Days 1, 2 and 3 as “categorical and probabilistic graphics that depict severe and general thunderstorm threats across the continental United States, along with a text narrative.” On Days 1 and 2, the outlook “contains individual severe probabilities for tornadoes, wind, and hail.” The probability numbers have a specific meaning worth knowing before you read one: “the probability values represent the chance of severe weather occurring within 25 miles of any point, which is about the size of a major metropolitan area.”

There is a second layer for the worst days. “Sometimes, a black hatched area will be overlaid with the severe probabilities. Black hatching means a 10% or higher probability for significant severe events within 25 miles of any point.” And significant is defined on the same page: ““Significant” is defined as: tornadoes rated EF2 or greater, thunderstorm wind gusts of hurricane force (74 mph) or higher, or hail 2 inches or larger in diameter.“

Hatching over your county on a wind day is the graphic a pet household should learn to read. It is the closest thing this hazard has to a cone.

There is even a longer horizon. A Day 4 to 8 severe weather outlook exists, issued “once a day by 400 am CST/CDT” and covering “the period of 72 to 192 hours from 1200 UTC on the morning of product issuance”, with two probabilistic thresholds, 15% and 30%. When neither is drawn, the text says so in one of two published phrases, “PREDICTABILITY TOO LOW” or “POTENTIAL TOO LOW”.

And the Storm Prediction Center’s own top category is defined using this exact hazard. Of its highest risk level the page states: “A 5-HIGH-magenta risk area suggests a severe weather outbreak is expected from either numerous intense and long-track tornadoes, or a long-lived derecho system with hurricane-force wind gusts producing widespread damage.”

So the map exists, several days out, and a derecho is what the top of its scale was written to describe.

The Documented Failure, Scoped to the Event That Produced It

Now the honest counterweight, and it comes from NOAA rather than from us.

After the June 29, 2012 derecho, the National Weather Service published a Service Assessment on its own performance. That document records a real advance-forecast failure:

“Unlike many major tornado outbreaks in the recent past, this event was not forecast well in advance. Warm-season derechos, in particular, are often difficult to forecast and frequently result from subtle, small-scale forcing mechanisms that are difficult to resolve more than 12-24 hours in advance.”

It names the models: the North American Mesoscale and Global Forecast System models “provided little assistance in forecasting this event more than 24 hours ahead of time. However, on the morning of June 29, some high-resolution, convection-allowing models began to provide clues that an intense line of thunderstorms could take the path that was later observed.”

And it names the map consequence directly. Many forecasters expected the system to break up crossing the Appalachians, and “This past pattern for such events impacted the SPC’s outlooks, which did not extend the risk for severe thunderstorms eastward to the Mid-Atlantic coast until the afternoon of June 29.”

That is the sentence a pet owner should sit with. A household in Maryland or Virginia planning around a Day 2 outlook on June 28, 2012 was not in the risk area. By the afternoon of June 29 they were, and the line arrived that night.

Scope that finding to the event that produced it. It disposes of the advance map for June 29, 2012. It is not evidence that Storm Prediction Center outlooks generally fail to map derechos, and the same outlook page quoted above defines its highest category using a derecho, which is not what an agency does with a hazard it cannot see coming.

What Did Work in 2012, Which Is the Half People Drop

The same assessment is emphatic that the warnings themselves performed:

“Despite the relatively short lead time for forecasting this event, the offices generally did an excellent job issuing warnings. Overall, lead times were greater than 30 minutes, especially on the eastern end of warning polygons. Most of the offices were issuing large warning polygons to cover the widespread nature of the event and the fast storm motion. All deaths occurred within severe thunderstorm warning polygon boundaries.”

Every death was inside a warning polygon. That single finding kills the no-warning story more decisively than any definition does, and it reframes the actual problem: not the absence of a warning, but what a household does with the thirty minutes it has.

One date fence has to be stated here and never crossed. The damage threat tags and the Wireless Emergency Alerts they trigger began on August 2, 2021. June 29, 2012 predates that by nine years. Nothing in this section should be read as saying phones alerted during that event.

The One Thing This Page Adds to the Pet Decision: The Clock

Everything above is decoding. This is the part that changes what a household with animals actually does, and it comes down to a speed.

Hours of System, Minutes at Your Address

A derecho is long-lived. The wind at one address is not, and conflating the two produces the “hours of 70 to 100 mph wind” version of this storm that circulates online.

What the sources record. The Storm Prediction Center: “Typically, derecho-producing storm systems move at speeds of 50 mph or greater, and a few have been clocked at 70 mph.” NOAA’s Service Assessment on the 2012 event: it “moved east-southeast at 60 miles per hour (mph) from Indiana in the early afternoon to the Mid-Atlantic region around midnight”, and it “traveled for 700 miles, impacting 10 states and Washington, D.C.”

Now the best-instrumented case for what a single location experiences. The National Weather Service forecast office in Des Moines documents the August 10, 2020 Iowa event, in a page whose summary block states it was last updated March 30, 2022. On the wind trace at the Des Moines airport: “One minute wind observations at the Des Moines International Airport (KDSM) on August 10, 2020 in the late morning showing a wind gust of 75 mph with wind gusts over 50 mph for over 20 minutes.”

Over 20 minutes above 50 mph, with a 75 mph peak, at an instrumented airport inside one of the most destructive derechos on record. The same page reports a research tower reading that is an instant rather than a duration: the Iowa Atmospheric Observatory tall tower near Zearing “shows a maximum, instantaneous 10 meter wind speed max of 46.71 m/s, which is 104 mph, at 11:26.38.”

That is the correct picture. Hours of system life. Tens of minutes of wind at your address. One pass, arriving at highway speed.

Which Is Exactly Why the Watch Is the Decision Point

Here is the join, and it is ours.

What the sources say. The Storm Prediction Center publishes the forward speed. The National Weather Service publishes that a watch area is “typically large, covering numerous counties or even states” and that a warning covers an area “around the size of a city or small county”. NOAA’s 2012 assessment records lead times “greater than 30 minutes” for that event. On bringing animals inside, the U.S. Food and Drug Administration states: “Bring your pets indoors as soon as local authorities say a storm is coming and have your pet emergency preparedness kit ready”, and “Keep animals in their carriers or crates.” The State of Michigan’s MIREADY pet page is broader in scope and states: “Always bring pets indoors at the first sign or warning of a storm or disaster.”

What the sources do not cover. The FDA document is titled and scoped to hurricanes and floods, and its evacuation trigger is storm surge, so it is not written about this hazard. We searched for a derecho-specific animal instruction on August 15, 2026, including federal and state emergency management and agriculture sources, and did not locate one. That is a description of what our searches returned, not a finding that no such document exists anywhere.

What this site concludes. A system moving at 50 to 70 mph shortens the interval between a warning polygon reaching your address and the wind reaching it, and unlike a hurricane’s, that interval does not lengthen as the event gets closer. The watch, which covers counties or states, is the last stage that is reliably ahead of the line. So animals come in and go into carriers at the watch, not at the warning, and the difference is not a preference: it is the difference between doing it calmly and doing it while a bow echo is thirty miles out.

That conclusion is consistent with the position this site already holds. Our crate or loose decision guide already tells readers to bring animals indoors at the first sign or warning rather than when a warning upgrades, and our mobile home tornado page already establishes that the decision point for leaving a manufactured home is the watch. What this page adds is the forward-speed number that explains why it is even more true here.

Three carve-outs ride with this advice everywhere it appears on this page, including in the checklist and the FAQ.

Manufactured and mobile homes. The instruction is to leave, not to settle animals into a room. The National Weather Service’s own severe thunderstorm warning entry says “Get out of mobile homes that can blow over in high winds”, and the Storm Prediction Center states that in a derecho “Mobile homes, in particular, may be overturned or destroyed”. Our mobile home tornado page works through what that evacuation costs a pet owner and how to make it survivable, and none of it softens into shelter in place.

If you are already in a vehicle. The National Weather Service does not tell you to stop and sit. It states: “In a Vehicle: Being in a vehicle during severe thunderstorms is safer than being outside; however, drive to closest secure shelter if there is sufficient time.” The Storm Prediction Center’s counterweight is that occupants of cars and trucks “are vulnerable to falling trees and utility poles” and that “High profile vehicles such as semi-trailer trucks, buses, and sport utility vehicles may be blown over.” Both are true at once. Closest secure shelter, chosen before you need it, not a long drive.

The confinement outlasts the storm. This third one is ours as well, and it is a join between the instruction above and a finding published further down this same page rather than anything a source writes about animals. Going into carriers at the watch means the animal is already confined when the wind arrives, and it is still confined when the outage arrives behind it: NOAA’s Service Assessment of the June 29, 2012 derecho records 34 heat-related fatalities after it in areas where the power was out, and the same report notes that most of those victims could not easily reach air conditioning. So put the carrier in the same secure room you would shelter in yourself rather than in a separate one chosen for quiet, keep water in it, and treat a confinement that outlasts the power as a heat decision as well as a wind one. Our heat emergency page for a house with no air conditioning is where that half of the problem is worked through properly.

The Crate Question Is Not This Page’s to Answer

Whether the dog goes in the crate or stays loose in the room with you is a real trade with a real answer, and this site already publishes an arbitrated one built on what FEMA, the ASPCA, American Humane, Humane World for Animals and NOAA actually say. It turns on whether the sheltering room can take on water, not on the name of the storm. Read crate or loose during the storm for the decision, the species split, the tether prohibition and the sizing rules.

The same goes for the mechanics of getting a large or reluctant animal into the sheltering room in the first place. Our page on getting a large or stair-refusing dog into a basement storm shelter covers the descent, and what to stock in a tornado safe room for pets covers what lives in that room permanently. If nobody is home when the warning lands, a dog home alone during a warning is the pre-set version of the same plan.

The derecho contribution to all of that is one word: earlier.

Outside the House: Kennels, Runs, Fences and the Car

This is the section where a household with animals loses things, and it is where the published record is thinnest.

What the Storm Prediction Center states, in its own words, about who and what gets hurt:

“Whether in an urban or rural area, those out-of-doors are at greatest risk of being killed or injured in a derecho.”

“Even those indoors may be at risk for death or injury during derechos. Mobile homes, in particular, may be overturned or destroyed, while barns and similar buildings can collapse. People inside homes, businesses, and schools are sometimes victims of falling trees and branches that crash through walls and roofs; they also may be injured by flying glass from broken windows.”

And its FAQ, on shelter for anyone caught out: “Falling debris is the most serious hazard posed by a derecho to those without shelter; cloud-to-ground lightning strikes are an additional hazard.”

The National Weather Service’s instruction for a person outside is unambiguous, and we are quoting it including the source’s own grammatical slip in the last clause: “Outside: Go inside a sturdy building immediately if severe thunderstorms are approaching. Sheds and storage facilities are not safe. Taking shelter under a tree can be deadly. The tree may fall on you. Standing under a tree also put you at a greater risk of getting struck by lightning.”

None of those passages is written about animals. So the next part is this site’s reasoning from them rather than a published instruction, and we searched on August 15, 2026 without locating a derecho-specific animal version of it.

A kennel building, a covered run, a carport and a shed are all inside the category the National Weather Service names as not safe. “Sheds and storage facilities are not safe” is written about people, and there is no reason in the physics for a structure that will not protect a person from a falling limb to protect a dog from one. If the plan for a derecho involves an animal remaining in an outdoor enclosure, that is the plan changing.

A shade tree over a run is the specific hazard, and the Storm Prediction Center says so about the neighborhood scale. It records “evidence to suggest that the impact posed by derechos has increased in recent years due, in part, to the maturation of shade trees planted in suburban areas in the 1950s and 1960s”, and describes post-war suburbs with overhead utility lines and older trees as “especially vulnerable to damage from high winds of any source.” The mature tree that makes a yard bearable in August is the same object the agency is describing.

A fence that holds a dog on a calm day is not the same fence after a panel goes down. That sentence is ours. It follows from wind that the Storm Prediction Center says can run “from 75 mph to greater than 100 mph” in places, and from the simple fact that a containment system is only as good as its weakest section. The consequence is not really about the fence. It is that an animal loose in a neighborhood after a derecho is loose among downed lines, broken glass and debris, which the Storm Prediction Center’s own after-the-storm guidance describes. What converts that from a lost animal into a returned one is work done in advance: current ID on the collar and a microchip registered to a phone number you still answer. Our microchip registration audit and what to put on a pet ID tag for a disaster are the two half-hour jobs that make the difference.

The car is not storage. The Storm Prediction Center’s vehicle sentences apply whether or not a person is in the seat, and a vehicle parked under a limb has the same exposure the agency describes for a vehicle in traffic. This is separate from the well-documented hazards of leaving an animal in a parked car at all, which our page on leaving a pet in the car at an evacuation stop works through.

Two Documented Events, and the Date Fence Between Them and Your Phone

Two derechos are documented well enough by NOAA itself, rather than by journalism, to be worth reading before a storm season. Both are used here for what they show about duration, damage and aftermath, and neither is used to say anything about phone alerts, for a reason stated at the end.

June 29, 2012, Ohio Valley to Mid-Atlantic. From the Service Assessment: it “traveled for 700 miles, impacting 10 states and Washington, D.C.” It moved at 60 mph from Indiana in the early afternoon to the Mid-Atlantic around midnight. “Winds were commonly above 60 mph with numerous reports of winds exceeding 80 mph. Some areas reported isolated pockets of winds greater than 100 mph.” Thirteen people were killed, “mainly by falling trees.” An estimated 4 million customers lost power for up to a week, and the executive summary records “some for more than a week after the storms moved through.” The region was in a heat wave at the time, and the assessment records “There were 34 heat-related fatalities after the derecho in areas where the power was out”.

August 10, 2020, Iowa and eastward. From the National Weather Service forecast office in Des Moines: “Widespread, destructive straight line winds blew across central Iowa during the day on August 10, 2020. The highest official wind gusts measured was 99 mph at the Marshalltown Airport with an unofficial wind gust of 106 mph at Le Grand (east of Marshalltown).” That page states the storm’s “path across the region on August 10, 2020 was over 750 miles!” Its preliminary estimated-wind map caption reads “There were to distinct locations of 100+mph winds with the area near Cedar Rapids estimating gusts of 120+mph!”, and we are reproducing the office’s own typographical slip in that sentence rather than tidying it. The page labels that map “preliminary and subject to change”, and that qualifier travels with the figure.

The date fence. The damage threat tags and the Wireless Emergency Alerts they trigger started on August 2, 2021. Both of these events predate that. The National Weather Service itself frames the Iowa event as a counterfactual, writing that the new destructive tag “would have activated a Wireless Emergency Alert for many of these impactful events, including the costliest thunderstorm in U.S. history,” the derecho that affected Iowa in August 2020. Would have. Any account that says phones alerted during either of these events is describing something that did not happen.

After the Line Passes: The Part That Lasts Longer Than the Wind

The wind at your address is minutes. The consequences run for days across a region, and this is the half of a derecho a pet household is least likely to have planned for.

The outage is regional, not local. The Storm Prediction Center’s Derecho Facts page explains the mechanism: derecho damage to overhead electric lines “sometimes results in massive, long-lasting power outages. Hundreds of thousands of people may be affected; in the worst events, power may not be restored for many days.” It adds why restoration is slow: “unlike the localized damage produced by a tornado, derecho damage may be widespread. As a result, repairs often require greater effort, with additional delays related to shortages in supplies.” The FAQ page phrases the duration slightly differently, as “in the worst events, power may not be restored for days”, and the 2012 assessment puts a number on one real case: 4 million customers, up to a week, some longer.

The places you would fall back to are inside the damage path too. The FAQ names both of them: “As with a hurricane, be aware that hotel and motel facilities may be impacted after the event, and that gasoline availability may be limited over a broad area.” A boarding kennel two towns over, a relative’s house on the other side of the county, and the tank of fuel that gets you to either are all assumptions worth testing against a 250-mile damage swath.

Heat is the documented killer after the wind. The 2012 assessment records 34 heat-related fatalities after the derecho in areas where the power was out, and adds detail that a pet household should read as a warning about its own dependencies: “Most of the victims were elderly and could not easily get to air conditioning locations. Many residents in remote areas had no water and could not refrigerate medication.”

None of those sentences is about animals. The join is ours, and it is short: the same outage that took the air conditioning took the aquarium heater, the oxygen concentrator, the well pump and the refrigerator holding insulin, and it took them across a region rather than a block. Our weeks-long outage pet plan is built on exactly the mismatch between backup runtimes measured in hours and restoration measured in weeks, and our heat emergency page for a house with no air conditioning is where the heat half belongs. For the everyday version, pets and power outages covers what depends on power and how to size backup for it.

The clean-up phase has its own casualty count. The Storm Prediction Center’s FAQ is direct about this and it is the sentence most likely to be skipped:

“Also watch for broken glass, upstanding nails, partially fallen tree limbs, and other hazardous debris. A sizable number of injuries and deaths related to derechos occur during clean-up operations — long after the storm has passed.”

Its instruction about lines is unqualified: “avoid any downed power lines and, especially, contact with lines in wet areas; the wires could still be “live.”“ And it adds a practical note people assume is unnecessary: “If you suffer a power outage from a derecho, do not assume that the utility responsible for your area is aware of the problem.”

Again, no source we opened writes that about a dog on a leash. Ours: the yard an animal walks into the morning after is the same debris field that hurts adults with gloves on, and a dog’s feet and nose are closer to all of it. Leash walks on pavement you can see, no off-leash access to the yard until you have walked it yourself in daylight, and no assumption that a fence line survived. Our ice storm page covers downed-line behavior and paw hazards in more depth, and the principle transfers cleanly.

The Derecho Checklist for a Household With Animals

Everything on this list is either quoted from a source above or explicitly marked as this site’s own reasoning in the section it comes from.

Before a season, on an ordinary afternoon:

• Call your county or parish emergency management agency and ask two questions: what triggers your outdoor sirens, and what the county’s own opt-in alert system is. Cherokee County, Georgia publishes the reason this cannot be answered from a web page: “Warning siren policies vary from county to county.”
• Set up an alert path that works indoors and while asleep. Dane County, Wisconsin states its sirens “should not be relied upon to be heard inside a structure” and that “If you are sleeping, an outdoor siren will probably not wake you up.”
• Do not let the phone be the only path. The National Weather Service’s damage threat table shows no Wireless Emergency Alert at the 58 mph base tier or the 70 mph considerable tier, and all Severe Thunderstorm Warnings continue to go out “via weather.gov, NOAA Weather Radio, Emergency Alert System and through dissemination systems to our emergency managers and partners.”
• If you live in a manufactured or mobile home, settle the destination now, not the room. The National Weather Service instruction for a severe thunderstorm warning is “Get out of mobile homes that can blow over in high winds.” Our mobile home tornado page covers what that costs a pet owner and how to make it work.
• Settle the sheltering room and stage a crate or carrier for every animal in it permanently. The crate-versus-loose trade itself is decided on our crate or loose page, and it turns on whether the room can take on water.
• Learn to read a Storm Prediction Center convective outlook, and specifically the black hatching, which the agency defines as “a 10% or higher probability for significant severe events within 25 miles of any point”, with significant including “thunderstorm wind gusts of hurricane force (74 mph) or higher”.
• Put current ID on every animal and confirm the microchip registration reaches a phone number you answer. A fence is a containment system with sections in it, and this is the layer that survives a section going down.
• Size the outage plan to days rather than hours, and to a region rather than a block. The Storm Prediction Center warns that after a derecho “hotel and motel facilities may be impacted after the event, and that gasoline availability may be limited over a broad area.”

When a watch is issued, which is this site’s decision point rather than any source’s:

• Bring animals indoors. The State of Michigan’s MIREADY page states “Always bring pets indoors at the first sign or warning of a storm or disaster.” The FDA publishes the same instruction and adds “Keep animals in their carriers or crates”, though that document is scoped to hurricanes and floods.
• Get the cat into the carrier now, while the cat can still be found. A system the Storm Prediction Center describes as moving “at speeds of 50 mph or greater” does not leave time to search the house later.
• Clear the yard of anything that becomes a projectile, and move a parked vehicle out from under limbs if there is a place to move it to.
• Put the carrier in the same secure room you would shelter in, and keep water in it. A crate closed at the watch stays closed through the wind and into the outage behind it, and NOAA’s 2012 Service Assessment records 34 heat-related fatalities after that derecho in areas where the power was out. Treating that confinement as a heat decision as well as a wind one is this site’s join from two findings on this page, not a published instruction.
• Charge what needs charging, fill water containers, and start the outage clock in your head rather than after the lights go.
• If you live in a manufactured or mobile home, this is when you leave, not when the warning arrives.

When the warning arrives:

• Go to your sheltering location. The National Weather Service states: “Take shelter in a substantial building”, and, on the pet question, “Take your pets with you if time allows.”
• Stay away from windows. The proposed Wireless Emergency Alert text reads “Take shelter in a sturdy building, away from windows. Flying debris may be deadly to those caught without shelter.”
• If you are in a vehicle, the National Weather Service says to “drive to closest secure shelter if there is sufficient time”, not to stop and wait it out.
• If you are outside with an animal and cannot reach a building, the Storm Prediction Center’s instruction for a person is: “Lie flat and face-down on low ground, protecting the back of your head with your arms. If possible, avoid trees; even relatively small branches can become lethal when blown by storm winds.” That instruction is written for people and no source we read extends it to handling an animal at the same time.
• Do not treat siren silence as an all clear. Knox County, Indiana states that “a siren turning off does NOT indicate that a threat is over.”

After the line passes:

• Walk the yard yourself, in daylight, before any animal goes into it. The Storm Prediction Center warns of “broken glass, upstanding nails, partially fallen tree limbs, and other hazardous debris” and states that “A sizable number of injuries and deaths related to derechos occur during clean-up operations — long after the storm has passed.”
• Treat every downed line as live, per the same page, and keep animals away from lines in wet areas specifically.
• Check the fence line before trusting it, and keep dogs leashed until you have.
• Report your outage rather than assuming the utility knows. The Storm Prediction Center says not to assume they are aware.
• Switch to the long-outage plan rather than the storm plan, and read our weeks-long outage page and heat emergency page for the two halves of it that actually kill animals.

What We Could Not Settle, and Where That Leaves You

Three honest boundaries, stated rather than papered over.

No derecho-specific animal guidance was located. We searched for state and federal emergency management and agriculture guidance addressing pets or livestock in a derecho on August 15, 2026, and did not locate a document written for that hazard and that audience. What exists and reaches this reader is storm-generic: the FDA’s hurricane-and-flood-scoped instruction, Michigan’s broader storm-or-disaster instruction, and the National Weather Service’s own “Take your pets with you if time allows.” That is a description of what our searches returned, not a finding that no such document exists. If your state extension service or emergency management agency publishes one, it outranks anything reasoned out here.

The Storm Prediction Center has one sentence that is easy to misread, and we are naming it rather than quoting it out of context. Its Derecho Facts page ends a paragraph with “In summary, the advance notice given by a derecho often is not sufficient for one to take protective action.” Read alone that appears to say derechos are unwarned. Read whole, it is not about warnings at all. Here is the paragraph it closes:

“Another reason that those outdoors are especially vulnerable to derechos is the rapid movement of the parent convective system. Typically, derecho-producing storm systems move at speeds of 50 mph or greater, and a few have been clocked at 70 mph. For someone caught outside, such rapid movement means that darkening skies and other visual cues that serve to alert one to the impending danger (e.g., gust front shelf clouds — see photos elsewhere on this page) appear on very short notice. In summary, the advance notice given by a derecho often is not sufficient for one to take protective action.”

That is about a person outdoors reading the sky, and the agency’s own FAQ page says the opposite about warnings: “Derechos rarely occur without warning, although warning lead times may be comparatively limited during the early stages of storm development.” Both are true. Visual cues are late. Warnings are not.

The definitions are in motion. The Storm Prediction Center’s page says so about itself, the journal paper it cites is explicitly a proposal, and the agency states that a comprehensive derecho archive under the modified definition is still being built. Everything numeric on this page is dated to August 15, 2026 and attributed to the specific document it came from. If you are checking a figure a year from now, open the Storm Prediction Center’s page rather than this one.

Where to Go Next

This page is one hazard spoke of our pet emergency playbooks hub, and it covers a single narrow situation: a long-lived, fast-moving windstorm that is warned, that only sometimes rings a phone, and that leaves a region without power behind it.

For the decision about the animal itself. Crate or loose during the storm is the arbitrated version of the confinement question and does not need to be re-decided per hazard. Getting a large or stair-refusing dog into a basement storm shelter covers the mechanics, and what to stock in a tornado safe room for pets covers what lives in that room year round.

If your home is a manufactured or mobile home. Tornado warning in a mobile home with pets is the page, and the instruction there does not soften for this hazard.

For the aftermath, which is most of the risk. When the outage is measured in weeks is the honest version of the outage problem, pets and power outages is the everyday version, and a heat emergency with no air conditioning is where the 2012 heat fatalities point.

For the alerting layer. Inland hurricane pet preparedness works through NOAA Weather Radio and the Wireless Emergency Alert list in detail, and evacuation levels decoded for pet owners covers the local ladder systems that exist for other hazards and not for this one.

Then do the single highest-value thing on this page, which takes one phone call. Ask your county emergency management agency what triggers your sirens and what its own alert system is, and set up an alerting path that works while you are asleep. Everything else here assumes you found out in time.