Nature Notes; Tornado Time in Texas

A tornado touched down near the town of Vealmoor, Texas, north of Big Spring, on May 5, 2015.

Photograph by Sunni Davidson

In West Texas, springtime means cacti blooms and birdsongs. It also means the advent of severe weather – from damaging winds to hailstorms. Perhaps no weather phenomenon is as extreme as a tornado.

West Texas sits at the edge of “Tornado Alley.” While tornadoes are more common to the east, our region can see powerful twisters.

When it comes to severe weather, the plains states have a dubious distinction. Along a wide path from Texas to Indiana called “Tornado Alley,” tornadoes occur more frequently than anywhere else on earth.

This unique weather phenomenon is the product of equally unique geography. From east to west, the Great Plains rise steadily in elevation toward the Rocky Mountains. Moist air from the Gulf of Mexico moves up the plains – until it meets the dry air of the desert West.

In spring, a distinct boundary forms between these two air masses. It’s called the dry line.

Rick Hluchan is a meteorologist with the National Weather Service in Midland.

“Your dew points east of the dry line may be in the 60s and 70, which is very moist,” Hluchan said. “It’s humid outside, you can really feel the thickness of the air. And then over a distance of 10 or 15 miles, the dew point might drop into the 20s and 30s.”

The location of the dry line can change from year to year. It often runs near Midland-Odessa.

It’s a fundamental principle: severe weather develops along boundaries. And the dry line can produce powerful storms.

The clash of air masses enhances spinning in the atmosphere, known as “sheer.” Sheer causes thunderstorms to rotate. If that rotation is close enough to the ground, tornadoes can develop.

“A lot of the storms rotate aloft, several thousands of feet up,” Hluchan said. “But for tornadoes we need that low level sheer – 700 feet, 1,000 feet in the air. It doesn’t happen that often down here – it happens more so up north – but we have seen some tornadoes around here, and some large ones at that.”

Hluchan said there have been at least three major tornadoes in West Texas in the last 30 years.

The most devastating occurred on May 22, 1987. It struck the town of Saragosa, south of Pecos. Many Saragosa residents were gathered in the school gym for graduation.

“Thirty people were killed in that tornado,” Hluchan said. “Unfortunately this was just a large tornado that went over a very small town, and many of the deaths here occurred at a school graduation, and many were small kids and babies. It was just unfortunate that the tornado hit this small town. Surrounding Saragosa you’ve got nothing but fields.”

Wind speeds were estimated at up to 200 miles per hour. A tornado of comparable power hit Bakersfield, east of Fort Stockton, June 1, 1990. Two motorists were killed. And on May 14, 2010, a powerful twister hit Notrees, flipping a pumpjack. There were no fatalities.

Strong winds are a more serious risk here than tornadoes. But Hluchan said that area residents should be aware that tornadoes do occur – and have plans for responding.

People should shelter in the center of their home – in a closet or other space without windows, as far as possible from the building’s exterior walls.

Many West Texans live in mobile homes. Mobile homes can be thrown by strong winds, and Hluchan said that residents should plan to shelter elsewhere.

“If you hear of severe weather coming, the best thing is to find another place,” he said. “You really want to look for a sturdy building. Even a car is not a good place. That’s something that people should be thinking about right now, before the severe weather hits.”

May is typically the peak time for severe weather. But the region’s weather is unpredictable, and tornadoes can occur any time of year. And the mountain country is not exempt. Hluchan’s office often receives photos of tornadoes between Alpine and Marfa.

Each spring, the weather service holds “Skywarn” classes across the region. The classes provide tips on how to read the skies for severe weather. They’re free and designed for officials and members of the public. Upcoming classes are scheduled in Alpine, Marfa and Odessa. For a full schedule, visit weather.gov/midland.

Nature Notes is underwritten by the Dixon Water Foundation and is produced by Marfa Public Radio in cooperation with the Sibley Nature Center in Midland, Texas. This episode was written by Andrew Stuart.