When we cannot feel wind, the air is calm. However, air is always moving even when we can't feel it. When hot air and cold air change places we feel the wind blow. Warm air rises and cold air sinks. Tornadoes are formed when warm air breaks through cold air and shoots up.
Tornadoes can form on both land and water.
When tornadoes form over water, they are called waterspouts. Waterspouts are like giant straws that suck up water and even fish. Later, both the fish and the water come raining down from the clouds.