Tornado Facts

Tornado season is March through June, although they can occur in any month of the year. The 2006 tornado season has gotten off to a violent start in the United States. There have been over 500 tornadoes between the beginning of the season in March through April. Texas alone has had many devastating tornadoes dating from the 1900’s to the present. The word tornado comes from the Spanish words tronado meaning thunderstorm and turnar meaning to turn.

Texas ranks number one for the frequency of tornadoes, the number of deaths, injuries and cost of damages. In 1970 the Texas population was 11,198,655 and between 1950 and 1995 Texas had 5,722 tornadoes. This ranked Texas number one in tornadoes by state.

Tornadoes are measured on the Fujita scale and are given a ranking of F-0 to F-5 depending on the destruction caused by the tornado.

A F-0 tornado has wind speeds of 42-72mph and will cause light damage. Examples of such damage include damaged chimneys, broken tree branches and shallow rooted trees are toppled.

A F-1 tornado has wind speeds of 73-112mph and causes moderate damage. Damage includes roof surfaces being peeled off and broken windows.

A F-2 tornado has wind speeds of 113-150mph and causes considerable damage. Damage includes roof structure damage, manufactured homes are destroyed, debris becomes airborne and large trees are uprooted.

A F-3 tornado has wind speeds of 158-206mph and will cause severe damage. This damage consists of roofs and some walls torn from structures, small buildings of will be destroyed and most trees in a forest will be uprooted.

A F-4 tornado has wind speeds of 207-260mph and causes devastating damage. Damage consists of well constructed houses being destroyed, some structures being lifted from their foundations and blown some distance, cars are also blown some distance and large debris becomes airborne.

A F-5 tornado has wind speeds of 261-318mph and causes incredible damage. Damage consists of strong framed houses being lifted off of foundations, reinforced concrete structures are damaged, automobile sized debris becomes airborne and trees are completely debarked.

On average tornadoes is 4 miles long and 400 yards wide, but can be as long as 100 miles long and a mile wide. The average travel speed of a tornado is 25-40mph but, can reach speeds of up to 70mph. The winds inside a tornado can swirl at close to 300mph. They stay on the ground for an average of 4-5 minutes and they can touch down several times. They produce the most violent winds on earth.

Tornadoes normally move from the southwest to the northwest and they rotate in a counterclockwise direction in the northern hemisphere and clockwise in the Southern Hemisphere. They normally occur between 3 and 7pm and they can be nearly invisible. They are marked by only swirling debris at the base of the funnel. Some are composed almost entirely of windblown dust and still others are composed of several mini-funnels.

The most remembered tornado in West Texas occurred in Lubbock County on May 11, 1970. It has been listed as the 10th most deadliest tornado in Texas since the 1900’s. The F-5 tornado killed 28 people, injured 500 and destroyed over 1,000 homes and apartment units, 10,000 vehicles and 100 aircrafts. This storm became an important development of the Fujita Scale.

Texas averages about 168 tornadoes a year and according to the National Weather Service 42 people are killed because of tornadoes each year in the United States. It is important to the facts about tornadoes and to be aware of tornado safety.