Tornado drill

The term "tornado preparedness" refers to safety precautions made before the arrival of and during a tornado. Historically, the steps taken have varied greatly, depending on location, or time remaining before a tornado was expected. For example, in rural areas, people might prepare to enter an external storm cellar, in case the main building collapses, and thereby allow exit without needing rescue from the main building as in urban areas. Because tropical storms have spawned many tornadoes, hurricane preparations also involve tornadoes. The term "tornado preparedness" has been used by government agencies, emergency response groups, schools, insurance companies, and others.

Preparedness involves knowing the major dangers to avoid. Some tornadoes are the most violent storms in nature. Tornadoes have varied in strength, and some tornadoes have been mostly invisible due to a lack of loose dirt or debris in the funnel cloud. Spawned from severe thunderstorms, tornadoes have caused fatalities and devastated neighborhoods within seconds of arrival.

A tornado operates as a rotating, funnel-shaped cloud that extends downward from a thunderstorm, to the ground, with swirling winds which have reached 300 miles per hour (480 km/h). The wind speed might be difficult to imagine: traveling the length of a U.S. football field within 1 second (over 130 meters or 430 feet per second). Damage paths have been in excess of one-mile wide (1.6 km) and 50 miles long (80 km).

Not all tornadoes are easily seen. A tornado funnel can be transparent until reaching an area with loose dirt and debris. Also, some tornadoes have been seen against sunlit areas, but rain or nearby low-hanging clouds has obscured other tornadoes. Occasionally, tornadoes have developed so suddenly, so rapidly, that little, if any, advance warning was possible.

Before a tornado strikes an area, the wind has been known to die down and the air to become very still. A cloud of debris has sometimes marked the bottom of a tornado even when the funnel was not visible. Tornadoes typically occur along the trailing edge of a thunderstorm.

The following is a summary of typical tornadoes:

The U.S. Federal Emergency Management Agency (FEMA) has advised the following precautions before a storm reaches an area:

Upon seeing an approaching storm or noticing any of the danger signs, they were advised to prepare to take shelter immediately, such as moving to a safe room, internal stairway, or other safe-haven area.

...
Wikipedia