Because the Earth is a small charged body moving in a large cell of plasma, explanations of all physical phenomena in, on, and near the Earth must take the electrical behavior of plasma into account. The waterspout shows us once again that plasma behavior can take many different forms.
There are two types of waterspout; one type is simply a tornado over water. The other (true waterspout) is less powerful than a tornado. It forms in a different way and often in a different season. It dissipates quickly if it happens to move over land.
Waterspouts occur in oceans or large lakes. They are common in the Great Lakes in months when the water is warmest--August, September, and October. They are most likely to occur when the water is warm, the air is cold and moist, and the winds are light. (They are predictable enough that the weather service issues waterspout warnings when conditions are right for their formation.)