Every spring there are a lot of strong storms.
More than 70 tornadoes formed in Oklahoma, Kansas, and Texas in one day. Some had hail as large as 11.4 centimeters 4.5 inches across. Scientists at NASA want to understand how these storms develop and how to better predict them. The most powerful thunderstorms have supercells. Supercells develop in parts of a thunderstorm where the wind is moving up or down very fast, which adds energy to the storm.