One Road Out: Bridge and Causeway Closure Thresholds, and How to Find Yours Before the Season

If one bridge, causeway or fixed link is the only way off the piece of ground your animals live on, your evacuation is governed by a deadline that most storm advice never mentions. It is not issued by the National Weather Service, it is not the county’s evacuation order, and it does not appear in the watch-and-warning timeline. It is the moment the structure itself stops carrying traffic, set by whichever agency maintains and polices that particular span, and once it lands the road out is simply gone. Everything else on this site treats departure as a weather call. On a single-egress property it is a capacity call first, because there is no second trip.

The number people repeat is 40 mph. That figure has real published backing in specific places, and it is not a national rule. Below are four Florida authorities, all fetched in August 2026, that give four different answers about their own structures, and three authorities in other states whose numbers, measurement methods and closure bands do not match Florida’s or each other’s. The point of assembling them is not to give you a table to look up. It is to show you why a table would be a lie, and then to hand you the procedure for getting the one number that actually governs your household.

Four Florida Authorities, Four Different Answers

Start inside one state, because that is where the generalization dies fastest.

Walton County Emergency Management publishes a hurricane FAQ that answers the question about a named structure directly. Asked at what wind speed the Clyde B. Wells (US 331) Bridge is closed, the county’s answer is one sentence: “The bridge is closed at sustained 40 MPH winds.” Elsewhere on the same page it expands slightly: “State and local law enforcement along with FDOT close bridges at a SUSTAINED 40 mph. Conditions can change at a moment’s notice giving little to no warning that the bridge will close.” That is a real, specific, sustained-wind threshold for a real, specific bridge, published by the county’s own emergency-management office. Note what kind of page it sits on, though. Walton’s FAQ is a live storm-status document whose other answers report the current posture, including whether evacuations or a local state of emergency are in effect at the moment you load it. Quote the rule from it, not the status.

Pinellas County published a notice on October 8, 2024, ahead of Hurricane Milton, whose subject was actually its three movable bridges. Following U.S. Coast Guard guidance the county planned to lock the Dunedin Causeway bridges, the Beckett Bridge and the Park Boulevard Bridge in the closed position at noon that day, and it noted that they “will remain open to vehicle traffic, but will not open for boat traffic until conditions are clear following the storm.” That is a distinct mechanism worth knowing about: a drawbridge can be locked down for marine traffic while still carrying cars. Then, in the same notice, the county stated the wind rule for the region’s fixed structures: “The Florida Highway Patrol and Florida Department of Transportation will close the Sunshine Skyway bridge when wind speeds reach about 45 mph. The Gandy Bridge, Howard Frankland Bridge and/or Courtney Campbell Causeway will be closed if wave action makes travel unsafe.”

Read that twice. Inside one county, the Skyway gets a number, and it is not 40. Three other major crossings get no number at all, because their criterion is wave action rather than wind. A household planning around “40 mph” and crossing the Courtney Campbell Causeway has planned against a rule that does not apply to their structure.

FDOT itself, in the statewide storm update it published on August 5, 2024 as Hurricane Debby came ashore, describes the statewide practice in language that is deliberately not a trigger: “Bridges in the potential impact area are closely monitored for flooding and wind speeds. Once wind speeds increase beyond 40 mph, FHP may deem it necessary for closure. Law enforcement will then stop traffic from crossing bridges to ensure the safety of motorists.” The number 40 appears, and so does the word “may.” The sentence does not say sustained, and it does not say gust. It describes a monitoring posture that authorizes a discretionary decision by the Florida Highway Patrol.

Lee County Emergency Management goes furthest, and it is the counterexample worth carrying. Its own one-page document, a file whose most recent revision date is July 2021 and which the county still links from its hurricane index under the heading “Will Bridges Be Closed?”, opens by rejecting the premise. Asked directly whether the county closes bridges during tropical storms and hurricanes, its answer begins:

“Lee County cannot literally “close” bridges during tropical storms or hurricanes.”

What follows in the same answer is an advisory rather than a closure. The county writes that it strongly advises drivers to stay off bridges, and off the roads leading to them, “when sustained winds reach 40 mph (tropical storm force).” It gives two reasons to treat that advisory as binding regardless: “At those speeds, wind gusts can already be much higher.” And: “Winds also become stronger at higher elevations, so dangers increase on higher bridges and elevated roadways.”

The county then explains why it does not barricade: “Lee County does not “close” bridges with barricades, cones, gates or signs because they can easily blow away, becoming ineffective and hazardous. We do not post law enforcement or other officials to manually restrict bridge access. If injured from blowing debris, those officials will be unable to respond when needed after the storm.”

And it names the consequence that makes the advisory worth obeying anyway: “Drivers who ignore the warning to stay off bridges face additional hazards if involved in a traffic accident because all emergency responders – fire, police, ambulance, tow trucks – cannot respond during tropical storm force winds.”

So in one state you have a county publishing a hard sustained number for a named bridge, a second county publishing a different number for one structure and a non-wind criterion for three others, the state DOT describing a discretionary practice with no stated measurement basis, and a third county stating that it does not close bridges at all and issues an advisory instead. Any page that hands you a single national figure has flattened all of that.

Now Cross a State Line

Outside Florida, the shape of the rule changes as much as the number does.

Chesapeake Bay Bridge-Tunnel: four levels, and an averaging basis

The CBBT publishes a formal document, the Chesapeake Bay Bridge and Tunnel Wind Advisory and Restriction Policy, marked “Effective July 1, 2022”. Its table is headed with a column the web version omits: “Average Wind Speed (mph)”. That heading is the measurement basis, and it is neither the sustained figure Florida counties use nor the gust figure a phone weather app shows you.

The bands, which the facility’s own live weather page reproduces with the same numbers, run: Advisory at 35 miles per hour, with the speed limit reduced to 45 mph and no passing. Level 1 at 40 miles per hour, at which the policy lists the vehicles that “will NOT be allowed to cross the facility”, beginning with motorcycles, large pick-up campers, camper trailers, house trailers and “Anything being towed”. Level 2 at 50 miles per hour, where the web page states that “The ONLY types of vehicles allowed to cross are: Cars without exterior cargo; Pick-up trucks (to include 2-axle, 6 wheels) without cargo; Mini-vans; Vans not to include high-profile/conversion vans; SUVs”. Level 3 at 60+ miles per hour: “Closed to all traffic due to weather conditions or safety concerns.”

Two details matter more than the numbers. The first is that Level 1, at 40 mph, is where a household towing anything loses the crossing while ordinary cars keep it. If your evacuation plan involves a trailer, a camper or a horse rig, your personal cutoff on this facility is 40, not 60. The second is the sentence the CBBT places directly above the table on its weather page: “Please note that these restrictions may change at any time.”

Maryland Transportation Authority: sustained and gusts, each with a clock

MDTA applies one scheme across its structures and is unusually precise about how the wind is measured, because it specifies a duration for each measure.

Note where you read it. The version most search results land on is an MDTA news post, and it carries its age on its face: the body ends with “UPDATED 5/18/15”, and the post is bylined May 19, 2015. The identical four paragraphs, word for word, also sit on MDTA’s maintained Bay Bridge emergency-closures page, which is the one to bookmark, and which adds a footnote the news post omits: “When a wind warning, restriction or closure is implemented at the Thomas J. Hatem Memorial Bridge (US 40), no bicycles are permitted.” The bands are still in force on both pages. The eleven-year-old stamp is a reason to confirm by phone, not a reason to discount the numbers.

The bands, in MDTA’s own words:

“Wind Warnings (sustained wind speeds of 30-39 mph for a continuous period of 10 mins or more; or wind gusts persistently exceed 30 mph over a period of 15 mins) operators of house trailers, box trailers, motorcycles, vehicles with roof-mount racks containing cargo or any other vehicle that may be subject to high winds are advised to use caution while traveling across the bridge.”

“Limited Wind Restrictions (sustained wind speeds of 40-49 mph for a continuous period of 10 mins or more; or wind gusts persistently exceed 40 mph over a period of 15 mins) house trailers, empty box trailers or any vehicle that, in the opinion of law-enforcement personnel, may not safely cross the bridge will be prohibited from traveling the bridge. Motorists who are denied passage will be assisted with safely turning around.”

“Full Wind Restrictions (sustained wind speeds exceeding 50 mph for a continuous period of 10 mins or more; or wind gusts persistently exceed 50 mph over a period of 15 mins) only automobiles, pickup trucks, flatbed trailers, commercial buses and heavy-laden tractor/trailers are permitted to cross the bridge.”

“Traffic Holds/Bridge Closure (sustained wind speeds exceeding 55 mph for a continuous period of 10 mins or more; or wind gusts persistently exceed 55 mph over a period of 15 mins) In the event of a sudden increase of sustained wind speeds or wind gusts that could jeopardize life or property, the MDTA may elect to discontinue the movement of all traffic across the bridge.”

Notice that 40 mph on an MDTA bridge is not a closure at all. It is the band at which house trailers and empty box trailers come off, and at which a trooper may turn away any vehicle that in their opinion cannot safely cross. Notice too that the closure band is written twice over: a numeric trigger at 55, and a separate discretionary clause allowing MDTA to stop traffic on a sudden increase. The number is the floor of the decision, not the whole of it.

Mackinac Bridge Authority: sustained only, said out loud

The Mackinac Bridge Authority answers the question on a Michigan Department of Transportation FAQ page, and it is the clearest statement of measurement basis we found anywhere. Its preamble does two jobs at once:

“Here are the speeds that trigger different wind warnings and closures. These speeds are not for gusts; they are sustained winds from any direction. These are minimum conditions resulting in advisories and closures but restrictions may be put in place at lower wind speeds if other hazardous conditions are present”

Its bands then run from “0-20 mph: No restrictions. Bridge speed limit is 45 mph” through a high wind advisory at 20 to 35 mph, mandatory escorts for high-profile vehicles at 35 to 50 mph, and a partial closure at 50 to 65 mph where “The bridge is closed to high-profile vehicles. Passenger vehicles that are not towing anything may cross but at no more than 20 mph.” Full closure arrives at “65 mph and above”.

The same page also answers where the wind is read: “The Mackinac Bridge Authority has wind gauges on the bridge that we use to determine wind advisories and closures.” That is the answer to a question most people never think to ask, and it matters, because a gauge on the deck of a long high-level span is not measuring the same air as the airport reporting station your weather app is quoting.

This authority is also the reason to stop thinking of closure thresholds as a hurricane topic. The Straits of Mackinac get no tropical cyclones. The bridge still closes for wind, and the number that closes it is 25 mph higher than the figure a Florida county publishes.

A Multi-State Survey Said All of This Out Loud in 2013

The dispersion above is not an accident of which pages we happened to fetch. The I-95 Corridor Coalition, a partnership of state DOTs and related agencies from Maine to Florida, surveyed its sixteen member states and published the results in September 2013 as its Bridge-Highway Closure Policies Survey. We looked for a more recent edition and did not find one; the document is still the version hosted on the successor coalition’s own site. Treat its state-by-state figures as thirteen years old and its structural findings as the reason this page exists.

Its headline finding on bridges:

“Bridge Closure Policies – Over half of the states (except Vermont, New Hampshire, Connecticut, Pennsylvania, New Jersey/non-metro New York City, North Carolina, and Georgia), close bridges when certain sustained wind speeds are reached, but these wind speed thresholds vary from 39 to 80 mph and are used as guidelines.”

A range from 39 to 80 across sixteen states is the whole argument against a national number. The survey’s other findings are, if anything, more useful to a household:

“With the exception of two sub-regions within two states, no states provided official documented policies for highway and bridge closures.”

“All States except Maryland and Georgia noted that closure triggers are used as guidelines and are not an automatic hard closure policy.”

“All state law enforcement agencies have the legal authority to close highways and bridges to all traffic. Additionally, many state DOT headquarters staffs have the authority to close highways and bridges to all traffic, but typically coordinate closely with law enforcement for approval.”

And in the detail section, the survey recorded that “South Carolina, Virginia, and Florida close bridges at 39-45 mph wind speed”, that “Delaware and Maryland close bridges at 50-55 mph wind speed, with some New York bridges closing to all traffic at 50 mph”, that “Rhode Island and New York close most bridges at 60-65 mph wind speed”, and that “Maine closes bridges at 80 mph wind speed.” It also noted a case where wind alone is not the criterion: “Massachusetts closes bridges at 39-45 mph wind speed if there are other conditions present such as snow, ice, freezing rain, driving rain, etc. that exacerbate the situation”.

Two cautions before you use any of that, and the second one is this page’s whole argument arriving on schedule.

Those are 2013 state-level self-reports, and several may have changed. We re-fetched two of them in August 2026. MDTA’s published bands still line up with the survey’s Maryland row, which put Delaware and Maryland at 50 to 55 mph. The CBBT does not line up with the survey’s Virginia row at all: the survey put Virginia in a 39 to 45 mph closure band, while the CBBT’s own Level 3 closure is 60+ average wind. That is not a contradiction to explain away, it is the point. The survey’s Virginia respondent was the state DOT, and the CBBT is an independent authority that writes its own policy for its own facility, so a state row and a structure rule were never the same object. We did not re-verify the other fourteen states, and you should not treat a thirteen-year-old survey row as your bridge’s current rule.

And a state-level figure is not a structure-level figure. Independent bridge and turnpike authorities set their own, as the CBBT and Mackinac examples show.

The Measurement Basis Is Half the Threshold

Line up what the authorities above actually measure and the problem becomes obvious.

Authority	Structure or scope	Published closure basis
Walton County (FL) EM	Clyde B. Wells (US 331) Bridge	Sustained 40 mph, no duration stated
Pinellas County (FL)	Sunshine Skyway	“about 45 mph”, measure not stated
Pinellas County (FL)	Gandy, Howard Frankland, Courtney Campbell	Wave action making travel unsafe, no wind figure
FDOT (statewide practice)	Bridges in the impact area	Beyond 40 mph, FHP “may deem it necessary”, measure not stated
Lee County (FL) EM	County bridges	No closure mechanism; advisory at sustained 40 mph
Chesapeake Bay Bridge-Tunnel	The facility	“Average Wind Speed” 60+ for Level 3 closure
Maryland Transportation Authority	MDTA bridges	Sustained over 55 for 10+ min, or gusts over 55 across 15 min
Mackinac Bridge Authority	Mackinac Bridge	Sustained from any direction, 65 mph and above, explicitly not gusts

Every row is quoted or paraphrased from the authority’s own published page or document, fetched August 2026 except where the source itself carries an earlier date. This is not a national table and it does not cover your structure unless your structure is named in it.

Four different bases appear in eight rows: sustained wind with no duration, sustained wind with a stated duration, an average, and a non-wind criterion entirely. A forecast reading of sustained 45 mph means three different things depending on which of those rows governs your road.

There is a further mismatch that trips people up in the last hours. NHC’s glossary defines the sustained wind it reports as “the highest one-minute average wind (at an elevation of 10 meters with an unobstructed exposure)”, and puts tropical storm force at “34 kt (39 mph or 63 km/hr)” on that same one-minute average. MDTA’s rule uses a ten-minute continuous window. The CBBT’s sheet says average. Mackinac reads its own gauges mounted on the bridge. None of those is the same instrument or the same arithmetic as the forecast on your phone, and a structure exposed high over open water routinely sees more wind than the nearest reporting station. When the two disagree, the gauge that closes the road wins.

Finding Your Own Structure’s Rule, Before the Season

This is the part that changes an outcome. It takes one afternoon in the spring and it does not need to be repeated often.

1. Name the structure exactly. Not “the bridge,” and not the road number. Bridges have official names and inventory numbers, and adjacent structures on the same highway can sit under different authorities.

2. Find who owns it, and who maintains it, because they can be different agencies. FHWA’s Specifications for the National Bridge Inventory (FHWA-HIF-22-017, March 2022) keeps them as two separate fields. Item B.CL.01, Owner, instructs states to “Report the agency that has ownership of the bridge using one of the following codes.” Item B.CL.02, Maintenance Responsibility, instructs them to “Report the agency that has primary maintenance responsibility for the bridge using one of the codes listed in Item B.CL.01 (Owner).” FHWA’s LTBP InfoBridge tool is where you look the record up for essentially every public highway bridge in the country; the field labels it shows come from that specification. Whichever agency is named may be a state DOT, a county, a city, or an independent bridge or turnpike authority. Independent authorities are the ones most likely to publish a formal written policy, as the CBBT does.

While you have that record open, check one more field. Item B.CL.06, Emergency Evacuation Designation, records “whether the route carried on the bridge is an emergency evacuation route”, and the specification’s commentary notes that “Emergency evacuation routes may be designated for various events such as hurricanes, earthquakes, tsunami, dam failure, and other hazardous events”, then sends the reader exactly where this page does: “Refer to the State Emergency Management Agency for designated emergency evacuation routes.” A Y in that field tells you your structure is somebody’s planning assumption, which is a reason to expect a published closure procedure to exist, not a promise that it will be easy to find.

3. Understand that the maintainer may not be the closer. The I-95 Corridor Coalition survey is explicit that “All state law enforcement agencies have the legal authority to close highways and bridges to all traffic”, and Walton County names three parties in one sentence: closure decisions “are made by the Florida Department of Transportation, Florida Highway Patrol, and Local Law Enforcement based on current conditions.” So ask the maintaining agency who actually makes the call for that span, and expect the answer to include a law-enforcement agency.

4. Ask six questions, in writing, and keep the answers. A number by itself is not actionable.

• What is the threshold at which this structure closes to ordinary passenger vehicles?
• Is it sustained wind or gusts?
• Over what averaging or duration period is it measured?
• Where is the wind measured, and can I see that reading in real time?
• Who makes the final decision, and does anyone else have to approve it?
• On which channel is the closure announced, and how far ahead?

5. Establish the restriction bands, not just the closure. On the CBBT and MDTA structures, towing something takes you out of service well below the closure number, but the two are not the same rule and flattening them is the exact failure this page is about. On the CBBT, Level 1 at 40 mph excludes “Anything being towed” outright, so a rig is off the facility at 40. On MDTA bridges, the 40 to 49 mph Limited Wind Restrictions band names only “house trailers, empty box trailers or any vehicle that, in the opinion of law-enforcement personnel, may not safely cross the bridge”, which makes a loaded horse or cargo trailer a trooper’s judgment call at 40 rather than an automatic exclusion; it becomes automatic at the Full Wind Restrictions band above 50, which permits only “automobiles, pickup trucks, flatbed trailers, commercial buses and heavy-laden tractor/trailers”. So your effective cutoff is the first band that excludes your rig, and you have to ask your own authority which shape its band has: a vehicle-type list, or a list plus an officer’s discretion. Households moving large animals should read that alongside the four-day planning horizon in our guide to loading and moving horses and other large animals before a storm, because a trailer restriction can bite before any wind advisory affects a car.

6. Subscribe to the right channel now. The survey found that “The vast majority of states utilize 511 and VMS to notify travelers of highway and bridge closures”, but an independent authority often runs its own feed instead. The Greater New Orleans Expressway Commission, which operates the Lake Pontchartrain Causeway, tells users to check its social accounts, to sign up for text or email advisories, or to “tune into 1700 AM Radio to hear up to date information about the bridge”, and states that “A yellow banner will be present on the website if an advisory is in effect.” On the pages of that commission’s site we fetched in August 2026, which were the home, safety, police and regulations pages, we did not find a published numeric wind threshold at all; what it publishes is the notification apparatus. That is a common pattern and it is precisely why step 4 is a phone call rather than a web search. Set up whichever channel your authority names before the season, and pair it with the route-monitoring tools covered in our guide to watching your evacuation route change in real time.

Working Backward From the Cutoff

Once you have a threshold with a basis attached, you can turn a wind number into a departure time.

The instrument for that is a National Hurricane Center product most people have never used. NHC publishes an Arrival Time of Tropical-Storm-Force Winds graphic in two versions, and describes the reason for both plainly: “The anticipated arrival of sustained tropical-storm-force winds from a tropical cyclone is a critical threshold for coastal communities. For example, emergency managers use this information to determine when to begin and complete coastal evacuations, while the public needs to know when to prepare their homes or businesses and get supplies. Once sustained tropical-storm-force winds begin, such preparations usually become too dangerous or difficult.”

The version you want is the conservative one:

“Earliest Reasonable Arrival Time: the primary graphic, which identifies the time window that users at individual locations can safely assume will be free from tropical-storm-force winds. Specifically, this is the time before which there is no more than a 1-in-10 (10 percent) chance of seeing the onset of sustained tropical-storm-force winds – the period during which preparations should ideally be completed for those with a low tolerance for risk.”

NHC contrasts it with the other version, which it says “would be more appropriate for users who are willing to risk not having completed all their preparations before the storm arrives.” A household that cannot make a second trip for its animals is not that user.

NHC also explains why the conservative graphic exists at all, and the reasoning applies directly to a one-road-out property: “Historically, many decision makers have inferred the arrival of sustained tropical-storm-force winds from NHC products deterministically, without accounting for tropical cyclone track or size uncertainty. The risk in not factoring in these uncertainties is that communities may have less time to prepare if a tropical cyclone speeds up or increases in size beyond NHC’s initial forecasts.”

Here is how to use it honestly. If your structure’s authority publishes a sustained threshold near tropical-storm force, and NHC puts tropical storm force at 39 mph on a one-minute average, then the Earliest Reasonable Arrival Time for your location is the right clock to plan the crossing against. That is a join you should make with your authority’s confirmation rather than on our say-so, because the measurement bases differ: a ten-minute MDTA window and a one-minute NHC average are not interchangeable, and a gauge on a high span reads before an inland station does. Ask, in step 4 above, whether your authority’s number is comparable to NHC’s sustained wind. If it is not, ask what forecast product they watch.

Then subtract, in this order, and use real numbers from your own household rather than optimistic ones:

• Capture. The time to actually have every animal in hand. This is the step that ruins single-egress plans, because it is the one with the widest variance and the least control. A cat that has decided not to be caught is a documented multi-hour problem, and our guide to getting a hiding or panicking cat contained exists because the emergency version of that job is nothing like the vet-visit version. Budget from your worst rehearsal, not your best.
• Loading. The physical work of getting containers into the vehicle in an order that holds. Our guide to how carriers and crates actually go into a vehicle when there are several animals covers the restraint and airflow side of that in full, and it is the load plan this deadline is applied to.
• The drive to the structure. Not the drive to your destination. The relevant leg is the one that ends on the far side of the span.
• The queue. On a single egress, everyone leaving uses the same asphalt at the same time, and the last hour before a cutoff is when the queue is worst. What that queue does to animals in a stopped vehicle is covered in our guide to what happens to pets when the traffic stops moving, and the short version is that the risks change character the moment the engine goes off.

Run it once, with your blanks in it, so the shape is familiar before the night you need it:

Earliest Reasonable Arrival Time for tropical-storm-force winds at my location, from the current NHC graphic minus my rehearsed capture time for every animal minus my rehearsed load time for the containers in the order they go in minus the measured drive from my driveway to the far side of the structure minus my own queue allowance for a single egress = the hour I leave.

We have not filled any of those in, because every one of them is yours and inventing a number here would be worse than leaving it blank. The only figure we can supply is the first line, and it comes from NHC on the day. The other four come from a stopwatch in the spring.

The result is a leave-by time that is usually earlier than people expect, and that sits inside rather than at the end of the watch-and-warning window described in our hurricane playbook for pet households. That playbook’s stages still govern what you do. The structure’s cutoff governs when the option to do any of it expires. The same subtraction, worked in more detail and against a county’s published clearance time rather than a structure’s wind threshold, is the whole subject of our guide to how early to leave with pets, and the two answers should be compared: your deadline is whichever comes first.

Why the Single Trip Is Not Negotiable

Everything above converges on one operational fact. On a normal evacuation, a household that misloads can turn around, come back and get the rest. Across a single structure with a closure threshold, the first trip is the only trip, and the decision about who and what is in it has to have been made before the driveway.

That reframes several ordinary questions.

Vehicle capacity stops being a comfort question. How many animals your vehicle actually holds, safely restrained, in one load is the whole answer, and our guide to how many animals genuinely fit in one vehicle is worth working through with a tape measure rather than an estimate.

Two vehicles may be worse than one. If a household splits across two cars and the cutoff lands between them, one driver is across and one is not, with the animals distributed between them. On a single egress, a convoy that departs together is worth more than a convoy that departs efficiently.

Boarding becomes a live option earlier. If the honest arithmetic says your household cannot capture, load and cross before the threshold, the alternative is not to try harder. It is to have decided in advance where the animals go instead, which our guide to choosing between boarding and taking them with you works through, and to have booked it while capacity existed.

A slow-loading animal changes the departure time, not the plan. A senior or mobility-limited animal, or one that needs to be lifted, adds real minutes at exactly the wrong moment; our guide to moving an older or disabled animal in an evacuation covers the equipment and technique, and the scheduling consequence belongs in the subtraction above. Multi-cat households should do the same arithmetic with our guide to getting several cats out at once, because capture time does not scale linearly with the number of animals.

None of this changes whether you should leave, which is a separate decision covered in our guide to choosing between sheltering in place and evacuating. It changes the latest moment at which leaving remains physically possible.

The Second Closure: After the Storm

The cutoff before the storm has a mirror image afterward, and it strands people on the far side from their animals rather than on the near side. It is worth understanding as a separate mechanism, because it runs on a different clock and answers to different people.

A structure that has taken a storm does not reopen because the wind dropped. It reopens after it has been inspected, and if it was damaged, after it has been repaired. Those two outcomes are separated by more than an order of magnitude in time.

Inspection is fast, when the structure survives. FDOT reported after Hurricane Idalia that “Over 100 Bridge Inspectors were deployed throughout the state, quickly clearing over 1,000 bridges through the main impacted areas. Less than 18 hours after the storm hit Florida, all state-owned bridge assessments had been completed.” In its August 5, 2024 landfall-day update during Hurricane Debby the following year, its statewide bulletin noted that “120 Bridge Inspectors are on standby to quickly deploy in the field” and that “Crews are staged to inspect coastal bridges and will be monitoring water levels at low-lying bridges near major river crossings”. A state that pre-stages inspectors can clear an undamaged network in under a day.

Repair is not fast. After Hurricane Ian, the Sanibel Causeway was the case that made this visible. FDOT announced on October 19, 2022 that “emergency repairs to the Sanibel Causeway have been completed in 15 days, more than a week ahead of schedule”, and its secretary described what had actually failed:

“While the bridges were largely undamaged by the storm, portions of the causeway which connect bridge structures together were washed away by Hurricane Ian, leaving the bridges unconnected to the mainland or the island. A project like this, under normal circumstances, could take months.”

That is the sentence to sit with if you live behind a causeway. The spans held. The earth between them did not, and the island was cut off regardless. FDOT’s release noted the population behind that link, describing crews working around the clock “to restore drivable access for the over 6,000 residents of Sanibel Island”, and framed 15 days as an exceptional result against a normal expectation of months.

FDOT’s release also names the handoff that catches people out: “Access to Sanibel Island via the Sanibel Causeway will be managed by Lee County.” A structure being physically passable and you being permitted to pass are two different gates, controlled by two different agencies, and clearing the first does not clear the second. The credential side of that, meaning re-entry stickers, checkpoint staging, escorted access and the channels that exist when your animal is inside a closed area and you are outside it, is covered in full in our guide to reaching a pet inside a closed zone. This page stops at the concrete.

The planning consequence for an animal household is specific and unwelcome. If you evacuate across a single structure, the honest assumption is not that you return when the wind stops. It is that you may be off the property for days or weeks, on a timeline set by an engineering assessment you cannot influence, and that anything left behind is on its own for that entire period. That is an argument for taking the animals rather than leaving them, and where taking them is genuinely impossible, for having read our guide to what the law actually says about leaving an animal behind before you are making the decision at speed.

It is also an argument for making the animals findable. If separation happens across a closed structure, the search runs without you for as long as the structure is shut, and our guide to finding an animal that has been separated from you after a disaster covers the channels that work in that window.

The Pre-Season Worksheet

Copy these into your evacuation plan and fill them in once, before a storm is named. Every blank is a question only your own authority can answer.

• Official name of my structure:
• Owner and Maintenance Responsibility agencies, per the National Bridge Inventory:
• Agency that makes the closure decision:
• Law-enforcement agency that enforces it:
• Closure threshold for passenger cars:
• Sustained, gust, or average:
• Duration or averaging window:
• Where the wind is measured:
• The band at which towing is prohibited (if I tow):
• Announcement channel, and how I subscribed to it:
• Phone number for the authority’s traffic or operations line:
• Second structure or route, if one exists, and its separate threshold:
• My household’s honest capture-plus-load time, from a timed rehearsal:
• My leave-by time when the Earliest Reasonable Arrival graphic shows tropical-storm-force winds at hour X:
• Who is on the animals’ side of the structure if I am not:

The last line is the one people skip and the one that matters most on a weekday. If your work, your school run or your errands routinely put a closable structure between you and your animals, the plan needs a named person with keys, written authority and a rehearsed destination, and our guide to getting an animal out when the order lands while you are at work covers how to set that up properly. The same problem arises when the animal is at a kennel or clinic on the far side, which our guide to what happens when your pet is at a facility and the order hits addresses directly.

What This Page Does Not Claim

We have quoted eight named road and bridge authorities, plus FHWA, NOAA’s National Hurricane Center and one multi-state survey, all fetched from the issuing organizations. We have not surveyed every bridge in the United States, and we cannot tell you your structure’s number. Nothing here should be read as a national standard, and the fact that four Florida authorities disagreed with each other is the reason.

Three specific limits are worth stating plainly. The I-95 Corridor Coalition figures are from September 2013 and cover sixteen states as they self-reported then; we found no newer edition, and several states may have revised their guidelines since. The Walton County answer sits on a live storm-status page that has no revision stamp, so treat the rule as current and the surrounding status as a snapshot. The Lee County document was last revised in July 2021 and remains the file the county links from its own hurricane index, which is why we treat it as current, but a county can change its posture without changing a PDF.

Everything on this page is quoted from the agency that published it, with its date where the source carries one. The only number that governs your evacuation is the one you get from the agency that closes your road. Go get it in the spring, while there is someone at the desk to answer the phone.

Where to Go Next

• The full hurricane playbook for pet households sets the watch-and-warning stages this cutoff sits inside.
• How early to leave with pets runs the same subtraction against your county’s published clearance time; whichever deadline is earlier is the one that governs.
• The T-minus storm countdown card is where a structure’s cutoff goes once you have the number, in the hour-by-hour sequence it belongs to.
• What happens to animals once the traffic stops moving picks up where this page ends, on the road you did get onto.
• Reaching a pet inside a closed zone covers the credential gate that follows the engineering one.
• How carriers and crates actually load into one vehicle is the plan this deadline is applied to.
• The hazard playbook hub collects the rest of the storm, fire and flood guidance for animal households.