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Severe Thunderstorm

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 is able to cause damage to property such as plants, roofs, and vehicles. Wind this strong is able to break off large branches, knock over trees, or cause structural damage. 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. Thunderstorms also produce dangerous lightning and heavy rain can cause flash flooding, but these hazards covered in more detail under the lightning safety and flood safety sections.

This website is designed to teach you how to stay safe in a severe thunderstorm. If you know what to do before, during, and after severe weather you can increase your chances of survival. You'll also find links to research, past events, other topics of interest, and downloadable materials about thunderstorms, lightning and tornadoes. If you, or someone you know, have been a victim of severe weather, please share your story so we can prevent others from becoming a victim. When you write, please note that NWS has permission to use your story and, if possible, let us know the town and state you were in and the year the event took place.