Severe weather is an annual occurrence in Texas and causes an average of 63 deaths per year. While severe weather is possible almost any time of the year, its occurrence varies significantly from January through December. General statistics show that North Texas, including the panhandle, has the highest risk for severe weather throughout the year. Severe weather also occurs in South Texas, but the number of events is usually lower in comparison to the north.
In order for severe thunderstorms to develop, a favorable weather environment is needed. When warm, moist air surges north from the Gulf of Mexico and collides with a cold airmass plunging south from Canada, thunderstorms are usually the result. Low pressure systems developing in between the two air masses are the triggering mechanisms for severe thunderstorms, including damaging winds, large hail, and tornadoes.
In the winter, (December-January-February), the greatest probability for severe thunderstorms is focused primarily along the southeast texas coast as periodic cold fronts collide with moisture from the Gulf of Mexico.
In the spring (March-April-May), the highest probability for severe thunderstorms begins in northeast Texas and shifts to the Texas panhandle as low pressure systems develop between the collision of warm and cold air masses. During this time, the risk for flash flooding also increases across central and southeast Texas.
In the summer (June-July-August), the best probability for severe thunderstorms slowly fades as high pressure builds over the entire state. The oppressive summer heat becomes the most significant severe weather feature. However, tornadoes and flooding are possible along the Gulf coast from an occasional tropical storm or hurricane.
In the fall (September-October-November), the greatest probability for severe thunderstorms shifts into central and southeast Texas as cold fronts return and collide with an abundance of Gulf moisture.
Closer examination of the statistics indicates that a majority of fatalities in the state occur from floods and flash floods, and of these, most occur in automobiles. Lightning, tornadoes, and high winds take an average 9 lives each year in Texas. Another major extreme weather event which claims an average of 15 lives each year is the summer heat.