Thunderstorms are common and can be dangerous. They can bring intense wind, flash flooding, hail and dangerous lightning. Severe thunderstorms are officially defined as storms that are capable of producing hail that is an inch or larger or wind gusts over 58 mph. Hail this size can damage property such as plants, roofs and vehicles. Wind this strong is able to break off large branches, knock over trees or cause structural damage to trees. Some severe thunderstorms can produce hail larger than softballs or winds over 100 mph, so please pay attention to the weather so you know when severe storms are possible.
Lightning strikes the United States about 25 million times a year. Although most lightning occurs in the summer, people can be struck at any time of year. Lightning kills about 20 people in the United States each year, and hundreds more are severely injured.
Severe Thunderstorm Watch: Be Prepared! Severe thunderstorms are possible in and near the watch area. Stay informed and be ready to act if a severe thunderstorm warning is issued. The watch area is typically large, covering numerous counties or even states.
Severe Thunderstorm Warning: Take Action! Severe weather has been reported by spotters or indicated by radar. Warnings indicate imminent danger to life and property. Take shelter in a substantial building. Get out of mobile homes that can blow over in high winds. Warnings typically encompass a much smaller area (around the size of a city or small county) that may be impacted by a large hail or damaging wind identified by a National Weather Service forecaster on radar or by a trained spotter/law enforcement who is watching the storm.
ready.gov/thunderstorms-lightning
National Weather Service Severe Thunderstorm Safety
FEMA Thunderstorm, Lightning, and Hail Fact Sheet
