Most of the time only one tornado occurs from the same wall cloud, but occasionally there can be more than one. Waterspouts Waterspouts are weak tornadoes that form over warm water. Waterspouts are most common along the southeastern states and the Gulf Coast. In the western United States, they occur with the cold late fall or late winter storms. The wintertime is when you would least expect tornado development, but they do occasionally occur.
Waterspouts sometimes move inland causing damage and injuries.
Before thunderstorms develop, an increase in wind speed and a change in wind direction with increasing height creates an unseen, horizontal spinning effect in the lower atmosphere. An area of rotation, 2-6 miles wide, now extends through much of the storm. Most strong and violent tornadoes form within this area of strong rotation. A lower cloud base identifies an area of rotation known as a rotating wall cloud. This area is often rain free.