Frequently Asked Questions

Every thunderstorm needs:

• Moisture: to form clouds and rain.
• Unstable Air:  relatively warm air that can rise rapidly.
• Lift:  fronts, sea breezes, and mountains are capable of lifting air to help form thunderstorms.

Developing Stage

• Towering cumulus cloud indicates rising air.
• Usually little if any rain during this stage.
• Lasts about 10 minutes.
• Occasional lightning during this stage.

Mature Stage

• Most likely time for hail, heavy rain, frequent lightning, strong winds, and tornadoes.
• Storm occasionally has a black or dark green appearance.
• Lasts an average of 10 to 20 minutes but may last much longer in some storms.

Dissipating Stage

• Rainfall decreases in intensity.
• Some thunderstorms produce a burst of strong winds during this stage.
• Lightning remains a danger during this stage.

Thunderstorms are most likely to happen in the spring and summer months and during the afternoon and evening hours, but can occur year-round and at all hours. Along the Gulf Coast and across the southeastern and western states, most thunderstorms occur during the afternoon. Thunderstorms frequently occur in the late afternoon and at night in the Plains states. Thunder and lightning occasionally accompany snow or freezing rain. During the blizzard of March 1993, lightning resulted in power outages near Washington, D.C.!

• From Lightning: People who are: outdoors, especially under or near tall trees; in or on water; or on or near hilltops.
• From Flooding: People who are in automobiles when flash flooding occurs near them.
• From Tornadoes: People who are in mobile homes and automobiles.