Mammatus clouds stretch over the sky as severe thunderstorms move through north Texas in the spring of 2015.
A supercell thunderstorm explodes over Celina, Texas on April 3, 2014.
An EF-4 tornado in Chickasha, Oklahoma throws debris in the air as a tow truck drives in the opposite direction escaping to safety. The tornado was part of major outbreak that took place on May 24, 2011.
