Understanding the Anatomy of a Tornado

Tornadoes are a destructive weather force, found most frequently in the Midwestern area of the United States. They occur in the spring and summer of the year, which results in the deaths of approximately eight people, and causing one thousand-five hundred injuries annually.

If you live in an area that is prone to tornados, this and additional information will assist you in preparing for your survival should disaster strike.

Definition: A tornado is high speed rotation of an air column, which extends from a thunderstorm to the ground below. They are capable of tremendous destruction, having wind speeds upwards of 250 mph or more. The damage path of a severe tornado is approximately mile wide, and fifty miles in length.

Causes: Thunderstorms happen where warm, moist air meets east-moving cold fronts. They often produce destructive hail, strong winds, and also the much-feared tornado.

Conditions needed:  Storms that produce tornadoes move east during the afternoon hours and may form a dryline. In the springtime, a meteorological "dryline" occurs in the Central Plains of the U.S. This line separates warm, moist air to the east, from hot, dry air to the west. Normally, thunderstorms will develop along this line.

In the front range of the Rocky Mountains, in the Texas panhandle, and on the southern High Plains, there are thunderstorms that form when air closer to the ground flows up towards higher elevations. These thunderstorms are also capable of producing tornadoes.

Tropical storms and hurricanes can spawn tornadoes as they move over land. They usually occur to the right and forefront of the storm as it comes ashore.

Water Tornado: A "waterspout" is a low-intensity tornado that forms over warm water. They are most common along the Gulf Coast of the U.S. In the west, they occur with relatively cold "early or late" winter storms. Waterspouts occasionally move inland, then becoming tornadoes that can cause property damage and injuries.

Formation of tornadoes: Prior to the development of a thunderstorm, a change in the direction and increase in the speed of the wind, along with increasing height, creates a transparent and horizontal vortex in the lower atmosphere. The rising air inside the thunderstorm updraft shifts the rotating air from horizontal to vertical.

A rotation, anywhere from two to six miles wide will extends through the storm. The majority of violent tornadoes form inside this area of rotation. A lower cloud base will identify the area of rotation, which is known as a rotating wall cloud. Shortly, a strong tornado will develop. This storm will also produce damaging hail that may be as large as a grapefruit.

Protect yourself: Listen to NOAA Weather Radio broadcasts, as well as local commercial radio and television stations. This will keep you informed of developments and information important to your survival. Before the tornado season, prepare a plan for your home or business. Have frequent drills to stay mindful of the method. Keep a NOAA Weather Radio with a warning alarm tone and battery back-up to receive warnings.

For more information: National Oceanic and Atmospheric Administration