Tornadoes travel at an average speed of 30 miles an hour, but speeds ranging from stationary to 70 miles an hour have been reported. While most tornadoes move from the southwest to the northeast, their direction of travel can be erratic and may change suddenly.
In populated areas, it is very dangerous to attempt to flee to safety in an automobile. Over half of the deaths in the Wichita Falls tornado on 1979 were attributed to people trying to escape in motor vehicles. While chances of avoiding a tornado by driving away in a vehicle may be better in open country, it is still best in most cases to seek or remain in a sturdy shelter such as a house or building. Even a ditch or ravine offers better protection than a vehicle if more substantial shelter is not available.
While hail may or may not precede a tornado, the portion of a thunderstorm adjacent to large hail is often the area where strong to violent tornadoes are most likely to occur.
Once large hail begins to fall, it is best to assume that a tornado may be nearby, and seek appropriate shelter. Once the hail has stopped remain in a protected area until the thunderstorm has moved away. This will usually be 15 to 30 minutes after the hail ceases.
The tornado's atmospheric pressure drop plays, at most, a minor role in the damage process.
Most structures have sufficient venting to allow for the sudden drop in atmospheric pressure. Opening a window, once thought to be a way to minimize damage by allowing inside and outside atmospheric pressures to equalize is not recommended. In fact, if a tornado get close enough to a structure for the pressure drop to be experienced the strong tornado winds probably already will have caused the most significant damage. Furthermore, opening the wrong window can actually increase damage.
While most tornado damage is caused by the violent winds, most tornado injuries and deaths result from flying debris.
Small rooms, such as closets or bathrooms, in the center of a home or building offer the greatest protection from flying objects. Such rooms are also less likely to experience roof collapse. Always stay away from windows or exterior doors.
Tornado wind speeds increase with height within the tornado.
Storm cellars or well constructed basements offer the greatest protection from tornadoes. If neither is available, the lowest floor of any substantial structure offers the best alternative. In high rise buildings, it may not be practical for everyone to reach the lower floors, but the occupants should move as far down as possible and take shelter in interior, small rooms or stairwells.
Tornado winds may produce a loud roar similar to that of a train or airplane.
At night or during the heavy rain, the only clue to a tornado's presence may be its roar. thunderstorms can also produce violent straight-line winds which produce a similar sound. If any unusual roar is heard during threatening weather, it is best to take cover immediately.
Although most tornadoes occur during the mid-afternoon or early evening (3 p.m.-7 p.m.), they can occur at any time; often with little or no warning.
The key to survival is advance planning. All members of a household should know where the safest areas of home are. Identify interior bathrooms, closets, halls or basement shelter areas. Be sure every family member knows that they should move to such safe areas at the first signs of danger. There may be only seconds to act. Have a tornado emergency plan at work.