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A waterspout is a rotating column of air mixed with water that forms over the surface of the water. However, waterspouts are different from tornadoes in various ways. Most waterspouts are less intense than tornadoes and will dissipate quickly after making landfall. Waterspouts form during unstable conditions when cool air moves over relatively warmer water.
The earliest stage of a waterspout consists of a rotating column of spray near the water surface. It may or may not be accompanied by a funnel extending downward from a cumulus type cloud. As the waterspout strengthens, the funnel will lengthen downwards towards the water. The waterspout reaches its mature stage when the funnel touches the water surface. It is at this point that the waterspout is at its greatest strength with associated wind speeds greater than 95 km/h.
Waterspouts occur any time during the day or night and are sometimes seen in families of two or more. They can last up to 20 minutes and have diameters ranging from 15 to 50 metres. They also move between 15 to 25 km/h.
The greatest threat by waterspouts is to small boats as well as to people along the shoreline. Waterspouts can capsize a boat or toss individuals overboard. They have also been known to knock down large trees along the shoreline.
If you are in a boat, move at a right angle to the movement of the waterspout. If onshore, move away from a tree.
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