Weather Research Centertm

FOR IMMEDIATE RELEASE

May, 6, 1999

With the recent outbreak of deadly tornadoes over the Midwest, Southeast Texas has been fortunate to have been sparred the wrath of these types of intense storms. Although Harris County has the most tornadoes sighted anywhere in Texas since 1950, there remains a very low risk of experiencing an F5 tornado. The high number of tornado sightings is attributed to the dense population the county boasts. If a tornado forms, it will likely be spotted and reported.

Overall since 1950, Texas has experienced six F5 tornadoes, the most recent being in Jarrell, 1997, when a killer tornado caused devastating destruction. According to Dr. John C. Freeman of Weather Research Center, conditions necessary for an F5 tornado (as rated on the Fujita-Pearson Scale) require that moist air be covered by very warm dry unstable air at altitudes of 5,000 feet and higher. "Harris County's close proximity to the Gulf of Mexico does not allow these type of conditions to develop and protects the Houston metro area from F5 tornadoes, since the air in the higher altitudes is moist due to the influence of the Gulf," stated Dr. Freeman.

Overall there have only been a few F4 tornadoes along the Upper Texas coast and there has only been one instance of an F4 tornado in Harris County since 1950. The most recent F4 tornado in the Houston area was the outbreak that occurred on November 21, 1992. That particular tornado struck the Channelview area near Interstate 10 and Beltway 8. Over 200 homes were destroyed and up to 1,000 damaged. Amazingly, there were no fatalities and only few injuries. Another example of an F4 tornado nearby was during Hurricane Carla in Galveston County on September 12, 1961.

Below is a table of all the F5 tornadoes which have struck the state of Texas:

Location Date Killed Injured

Waco May 11, 1953 114 597

Wichitha Co. April 3, 1964 7 111

Lubbock Co. May 11, 1970 26 500

McLennan Co. May 6, 1973 0 0

Brown Co. Apr 19, 1976 0 11

Jarrell May 27, 1997 27 24

In general, Texas has the highest number of tornadoes anywhere in the country. During the period of 1950-1994, Texas recorded 5,490 twisters. Following in a distant second place was Oklahoma with 2,300. During the same time period, Texas had the highest number of tornado-related fatalities (475), the highest injuries (7,452) and the highest in post-storm damages ($1,955,927,552).

During 1950-1994, the state (within the lower 48 contiguous states) with the least number of twisters was Rhode Island with eight. Alaska reported only one tornado while Hawaii had 28. Tornadoes can develop at any time during the year, but are more common during the Spring months of March, April and May when warm, moist air from the Gulf of Mexico collides with cool, dry air from Canada.