Identify the characteristics of a severe storm

According to the National Severe Storms Laboratory, a thunderstorm is a rain shower that is accompanied by thunder and lightning, and it may also involve string winds, sleet, or hail. A thunderstorm becomes severe when it develops hail larger than an inch in diameter, wind gusts in excess of 57.5 mph, or a tornado.

Severe storms are atmospheric disturbances usually characterised by strong and hazardous winds, frequently combined with heavy rain, snow, sleet, hail, ice and/or lightning and thunder. This definition includes unusual meteorological disturbances, such as tornadoes or waterspouts, caused by severe thunderstorms.