Storms that bore down on Southern Plains states brought powerful winds that upended a tractor-trailer on an Oklahoma interstate, killing the driver, while three storm chasers died in a collision as they raced toward a tornado-warned storm in West Texas, authorities said.

The storms that struck Texas and Oklahoma late Tuesday brought tornadoes, tennis ball-sized hail and powerful winds, but no widespread damage was reported. It’s just the beginning of what’s expected to be a stormy week in Tornado Alley and in parts of the South.

In Oklahoma, the truck driver was killed after strong winds pushed his rig off the interstate in El Reno, outside Oklahoma City, according to the Oklahoma Highway Patrol. Forecasters confirmed a 95 mph (150 kph) wind gust in the area when the crash occurred.

In Texas, the three storm chasers — including two who were contractors for The Weather Channel — were killed in a collision at a remote intersection near the town of Spur, about 55 miles (90 kilometers) southeast of Lubbock.

The channel said in a statement that Kelley Williamson and Randy Yarnall were “beloved members of the weather community” who had worked as contractors for the channel. The Texas Department of Public Safety said the two died Tuesday along with another storm chaser, 25-year-old Corbin Lee Jaeger of Peoria, Arizona.

Williamson and Yarnall were both from Cassville, Missouri.

Department of Public Safety Sgt. John Gonzalez says a Chevrolet Suburban driven by Williamson ran a stop sign and slammed into the Jeep driven by Yarnall with Jaeger as passenger, killing all three instantly. Tornadoes had been reported nearby at the time of the crash and heavy rain had been reported in the area.