What to know as tornado season is about to start in Texas
The last day of meteorological winter is Feb. 29, and meteorological spring is set to begin on Friday. Here in Texas, spring means that temperatures will rise, rain chances will increase and the bluebonnets will bloom across the Lone Star State.
But it also means severe thunderstorms will become more frequent. More specifically, Texas is about to reach the time of the year when tornadoes become a big risk. You may think that tornadoes really aren't a big concern until April and May, but March is truly when tornado season starts in the Lone Star State.
Here are the numbers
Tornadoes can happen in Texas during any month of the year, but the vast majority happen in a four-month span from March through June. Over the past 20 years, Texas has averaged close to 15 confirmed tornado reports every March, which equates to about one tornado every two days, according to National Weather Service local storm reports.
That is about five times more tornadoes than occur in February. It also makes March the month with the third-highest tornado total in Texas. The only two months that average more twisters are April and May.
More recently, March has started to see an even greater frequency of tornadoes. Since 2016, Texas has averaged 25 March tornado reports each year. Because that's only eight years of data, It's likely not long enough to be considered a new trend. However, the increase could be tied to our warming climate, as spring weather has gotten an earlier start over the past decade.
What causes the increase in tornadoes?
Tornadoes become more common in the spring partly because moisture levels increase tremendously in March, and that trend continues into April and May.
During the winter, dew points across Texas are often less than 50 degrees, which indicates rather dry air. By March, dew points rise into the 60s and even 70s as southerly moisture-rich winds increase out of the Gulf of Mexico. These higher moisture levels are fuel for severe thunderstorms capable of producing tornadoes. That's a big reason why Texas averages the most March tornadoes of any state in the country.
High moisture levels alone won't create tornadoes. You also need something to tap into all that moisture and energy. From March through May, strong systems of low atmospheric pressure regularly dip southward and affect the Lone Star State.
These systems can spark thunderstorm formation and create wind shear in the atmosphere. Wind shear happens when winds change speed and direction as you move up in the atmosphere. It's a big reason why thunderstorms are able to develop into rotating supercells, capable of producing tornadoes.
Recent March tornadoes
We have recently seen a few large tornado outbreaks in Texas during March.
• 2022: On March 21-22, more than 30 tornadoes touched down in the Lone Star State. The strongest tornado was an EF-3 that tore through Jacksboro in North Texas, northwest of Fort Worth. Several EF-2 tornadoes also affected Central Texas communities in Round Rock, Elgin and farther north in Grayson County.
• 2023: Just last year, five tornadoes touched down on March 2 in East Texas. Three more touched down in North Texas two weeks later, on March 16.