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Mackinac Bridge Wind

  • 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:

    • 0-20 mph: No restrictions. Bridge speed limit is 45 mph.
    • 20-35 mph: High wind advisory. High-profile vehicles (RVs, trailers, etc.) should travel no faster than 20 mph across the bridge.
    • 35-50 mph: Escorts required. Any high-profile vehicles must wait to be escorted across the bridge. Escorts ensure that high-profile vehicles travel at speeds of less than 20 mph, depending on conditions.
    • 50-65 mph: Partial closure. The bridge is closed to high-profile vehicles. Passenger vehicles that are not towing anything may cross but at no more than 20 mph.
    • 65 mph and above: The bridge is closed to all traffic.
  • The current procedures were developed primarily through years of experience, learning what wind speeds cause issues for particular vehicles. We’ve learned lessons from previous incidents, improved the devices we use to measure the wind, the way we convey that information through message boards and the bridge radio station, and have continued to improve by sharing information through Twitter, texts, and webcams.

  • When considering a high-wind escort or partial closure, high-profile vehicles would include but are not limited to:

    • Semi-tractor trailers
    • Recreational vehicles and campers
    • Pickup trucks with cappers, tonneau covers, or any items in the truck bed
    • Panel trucks and vans
    • Enclosed trailers (such as snowmobile or ATV haulers)
    • Open trailers that are hauling anything
    • Work trucks that have toolboxes, ladders, or other equipment mounted to the truck bed
  • Though our maximum speed limit on the bridge is 45 mph (and lower during high wind conditions), unfortunately we have seen many tonneau covers that stay on at freeway speeds come loose on the bridge. For whatever reason, high wind at the Straits seems to be stronger than tonneau fastening systems. When a tonneau cover comes loose, it can become a hazard for other motorists, a danger to our staff if they are called to retrieve it, or it’s just more trash blown into the Straits. The same is true for any items inside an open truck bed. For those reasons, we don’t allow them during partial closures.

    Camper awnings are allowed during escort conditions; but as all campers are high-profile vehicles during partial closures, awnings aren’t called out separately in our policies. However, unsecured awnings do pose similar hazards during high winds, so we urge travelers to ensure their awnings are firmly secured and attached before crossing the bridge. 

  • The Mackinac Bridge Authority has wind gauges on the bridge that we use to determine wind advisories and closures. 

  • Wind direction is less of a factor than wind speed. Winds are typically from the west/northwest in the Straits, but sometimes it does come from different directions. What’s most important is for drivers to slow down during high wind events so they can maintain control of their vehicles regardless of wind direction. 

  • Our escorts, led by MBA vehicles, keep escorted vehicles to speeds of 20 mph or less. Slower speeds help drivers of high-profile vehicles maintain control during high winds.

  • The main difference is where vehicles queue for escorts. On the north side of the bridge, southbound high-profile vehicles will line up just past the toll booths on the west side of the bridge approaches. On the south side, northbound vehicles will line up on the east side of the bridge approaches, just past Jamet Street (Exit 339). High-profile vehicles must remain queued until an MBA vehicle arrives to escort them across.

  • During inclement weather (and we consider high winds inclement weather), we urge drivers to turn on their lights so they are visible to other drivers, slow down so they can maintain control of their vehicles, and stay in the outside lane as that is the lane for slower traffic (it has nothing to do with the deck grating versus paved surfaces). 

  • Drivers who do not feel comfortable driving across the Mackinac Bridge can have staff from the Mackinac Bridge drive their vehicle through the Driver Assistance Program. Drivers and passengers must be 18 years of age or older. The required liability waiver has been updated, and staff will complete a checklist of several items the customer must agree to, including allowing for adjustments of mirrors and the driver’s seat, using a dash camera to record the inside of the vehicle during the crossing, keeping any animals in the vehicle restrained, having all occupants wear a mask covering their nose and mouth, and allowing the vehicle to be cleaned before crossing.

    This service is available 24 hours a day, 7 days a week. The cost is $10 per vehicle, plus the appropriate toll for the vehicle driven. To request from the north side, request the service from inside the administration building or at the toll booth. To request from the south side, pull over on the wide shoulder just north of Exit 339 near the booth and call Bridge Services (906-643-7600) to request this service.

  • We do issue warnings when the bridge deck is icy, which is particularly noteworthy because we do not apply salt due to concerns about corrosion of the bridge’s steel components. Though rare, we have closed the bridge for whiteout conditions, freezing rain events coupled with high winds, and, of course, falling ice events (see our FAQs about falling ice). It’s not a weather event but there’s also a little event each Labor Day, the Annual Bridge Walk, which results in a morning bridge closure to traffic. 

  • We always post current conditions and any advisories or closures on our website: We also tweet those updates on our Twitter account: @MackinacBridge.

    People who are interested in receiving text messages about bridge closures, including closure information for the Annual Bridge Walk, can sign up for Mackinac County 911’s RAVE Alert System updates. There is no cost to receive these updates, aside from any texting fees from the participant’s mobile coverage plan. To opt into this text alert system, text “MacBridge” to 67283.

    As drivers approach the Mackinac Bridge, advisories are posted on our dynamic message signs on US-2 and I-75. During closures, the Michigan Department of Transportation (MDOT) helps post information on their message signs farther away from the Straits. Once in the Straits area, drivers can tune to AM radio 530 or 1610 for updates.

    We also have current camera views of the bridge on our website, if that helps drivers make travel decisions:

  • No vehicle has ever “blown off” the Mackinac Bridge. Despite the rumors and legends, it’s never happened.

    More than 200 million vehicles have crossed the bridge since it opened in November 1957. Only two vehicles have ever gone over the railing of the bridge:

    • On Sept. 22, 1989, a Yugo compact car went over the railing. A police report of the incident estimated that the vehicle was traveling at more than 60 mph. While wind could have been a contributing factor, it did not blow the vehicle off the bridge.
    • In March 1997, a Ford Bronco went over the railing. That case was later ruled a suicide.

    Both incidents were terrible tragedies but were not the result of wind blowing vehicles off the bridge. The hazards of high winds, however, are why we issue advisories and close the bridge during extreme wind events.

  • There have been a few other instances where winds have caused high-profile vehicles to tip over on the bridge. In July 2013, a truck tipped against the bridge railing. In December 2022, a mobile office trailer tipped over against the bridge railing. In both cases, the bridge was closed until the vehicles could be cleared. The railings were not damaged. 

  • Nope, and it doesn’t bounce either. The deck of the bridge is designed to be somewhat flexible, moving up and down slightly as the distribution of weight changes from vehicles (and pedestrians during the bridge walk). While a sustained wind can cause the suspended span to deflect slightly, the bridge doesn’t sway. Any movement you would feel is from the wind, not movement of the bridge. 

  • Staff does its best to separate high-profile vehicles during those times, and while semi-tractor trailers and recreational vehicles are easy to spot, they’re also trying to catch pickups with cargo or tonneau covers and other vehicles that might have an issue during very high winds. However, we’re not a law enforcement agency, so we’re mostly relying on cooperation to make sure those hazardous items don’t make it out on the bridge. We will contact law enforcement about drivers who fail to comply with our policies, including drivers of high-profile vehicles who do not stop for escorts or partial closures. 

  • Confirmed by our partners with the Michigan State Police, it is illegal to drive with an unsecured load, and unfortunately, troopers see this a lot while out on patrol. Penalties can range from a simple civil infraction ticket all the way up to a felony if the unsecure load causes death of another motorist. Our staff is put in harm’s way unnecessarily when they need to go out onto the bridge to retrieve items that have blown off or out of vehicles and trailers. We don’t want to see that happen, so we urge drivers to check and double-check their loads before starting across the bridge.