Del Rio, TX was raked with hail two inches in diameter, and wind gusts to 112 mph. Brown County and Commanche County in TX were deluged with up to 18 inches of rain, and flooding caused more than 65 million dollars in damage. . The National Weather Service uses wind speed and hail size to define official severe thunderstorms. A thunderstorm is declared severe by the NWS if wind gusts reach 58 mph or stronger, or if hail size is three quarters of an inch or bigger. A thunderstorm only needs to meet one of the above criteria to be declared severe.
Lightning is a danger with all thunderstorms, regardless of severity.