WHAT IS A TORNADO?
A tornado is a violently rotating column of air that descends from a thunderstorm down to the ground. It’s one of nature’s most terrifying and destructive weather phenomena. Tornado intensities are classified on the Fujita Scale with ratings between F0 (weakest) to F5 (strongest). The most violent tornadoes are capable of tremendous destruction with wind speeds of 250 mph or more. Damage paths can be in excess of one mile wide and 50 miles long. They can destroy large buildings, lift 20-ton railroad cars from their tracks, and drive a blade of straw through a telephone pole. In a typical year, more than 1,200 tornadoes occur throughout the vast United States.
Tornadoes can occur any time of the year, but in Alabama they are most common from March until May. The state averages 23 storms per season. In Alabama, tornadoes almost always travel from the southwest to the northeast. This pattern can be seen in all of the tornado tracks of April 2011.
More Tornado Facts
When a Tornado Watch is declared, tornadoes are possible in and near the watch area. This is a time to review and discuss your emergency plans and check supplies for your safe room. Be ready to act quickly if a warning is issued or you suspect a tornado is approaching.
The means a tornado has been sighted or indicated by weather radar. Tornado warnings indicate imminent danger to life and property. Go immediately underground to a basement, storm shelter or an interior room (closet, hallway or bathroom). NO part of a mobile home is safe during a tornado.
MYTH: Areas near rivers, lakes, and mountains are safe from tornadoes.
FACT: No terrain is safe from tornadoes. In the late 1980's, a tornado swept through Yellowstone National Park leaving a path of destruction up and down a 10,000 ft. mountain. Never assume you know what a tornado is going to do. Always assume tornado warnings are meant for you.
MYTH: The low pressure with a tornado causes buildings to "explode" as the tornado passes overhead.
FACT: Violent winds and debris slamming into buildings cause most structural damage.
MYTH: Windows should be opened before a tornado approaches to equalize pressure and minimize damage.
FACT: Opening windows allows damaging winds to enter the structure. Leave the windows alone; instead, immediately go to a basement, interior room, or bathroom without windows.