What is the difference between hurricanes and tornadoes?
Hurricanes and tornadoes both involve heavy winds that rotate around an area of low pressure. Both types of storms have intensity rating systems based on wind speed. Hurricanes can also sometimes produce tornadoes. Hurricanes always rotate counterclockwise in the northern hemisphere and clockwise in the southern hemisphere due Earth's rotation (Coriolis effect). Tornadoes usually follow this pattern, but can sometimes spin in the opposite direction because tornadoes are influenced more by local winds. The two storms differ in other important ways. Hurricanes are massive storms that only form over oceans. Heat from ocean water provides the energy that drives hurricanes. Tornadoes are much smaller and typically form over land where warm air masses run into cold air masses in the same weather systems that produce thunderstoms.