Thunderstorms usually last for 30 minutes to an hour. They can happen in a singular fashion, in lines or in clusters. Some of the most dangerous thunderstorms happen when a single storm strikes in a location for a lengthy period of time.
Weather conditions that are humid and warm typically can cause a thunderstorm. That's why many thunderstorms happen in the spring and summer. Lightning accompanies the thunderstorms and can strike up to 10 miles away from the rain. The term heat lightning is used for lightning that is so far away that the thunder can't be heard. Only 10 percent of thunderstorms are considered adverse. Severe conditions can create hail as well as winds of at least 58 miles per hour or more.
Severe thunderstorm watches are designed to let people know where a severe thunderstorm may happen. A severe thunderstorm warning is released when dangerous weather has been detected by a radar or onlookers. A warning means that there can be immediate trouble to property as well as a person's well-being, and on rare occasions, injuries and even death can occur from a severe thunderstorm. Lightning can strike individuals who are outside during a summer afternoon or evening, although the chance of this happening is 1 in 600,000.