Many people mistakenly think that a highway overpass provides safety from a tornado. The reality is: an overpass may be one of the worst places to seek shelter from a tornado. An overpass as a tornado shelter can put people at a greater risk of being killed or seriously injured by flying debris from the powerful tornado winds.
Wind speeds in tornadoes can exceed 200 mph. These destructive winds produce airborne debris that are blown into and channeled under the overpass where people might try to seek shelter. Debris of varying size and types, including dirt, sand, and rocks, moving at incredible speeds can easily penetrate clothing and skin, causing serious injuries and possibly death. Very fine debris can also be forced into eyes, causing injury or loss of sight. A person can even be blown out or carried away from the overpass by the fierce tornado winds. If a person is positioned at the top of an overpass, he/she could encounter even higher wind speeds and more missile-like debris. Wind direction will also shift abruptly as the tornado passes, tossing debris from all sides.
- Flying debris become dangerous missiles in the tornado airflow
- By climbing up higher under an overpass, people will be exposed to higher wind speeds and more flying debris
- The narrow passage underneath an overpass could cause an increase in the wind speed under the bridge
- Most overpasses don't have girders or support beams for handholds
- If an overpass is directly in the path of a tornado, the wind could change direction by nearly 180 degrees as the vortex passes
When a tornado approaches, the safest course of action is to get out of the tornado's path. Seek shelter in a sturdy, well-constructed building.
Do not stay in your vehicle. Do not try to outrun a tornado. If you cannot seek shelter in a building, lie flat in a ditch or ravine and clasp your hands behind your head to protect yourself from flying debris.
Be aware of weather conditions. Listen to a local radio station to stay up-to-date on changing conditions.
Remember: Overpasses offer NO PROTECTION from tornadoes and should not be used as sheltering areas.