These highly destructive whirlwinds are created when cooler upper level air masses have much different air pressure than the air at ground level. If an unusual condition exists in which a warm air mass is inserted underneath a cold air mass, the warm air wants to rise. Hurricanes are extremely large, flat whirling air masses, usually hundreds of kilometers across. The wind speed in a hurricane can reach more than two hundred kilometers an hour. The destruction a hurricane can wreck on the land can extend over several states and cost several billion dollars.
Hurricanes come into being over the ocean far out to sea.
The destruction occurs when the high speed hurricane winds reach land and blow down structures and vegetation. If a lightning bolt hits a tree, the thermal energy released into the tree can cause the sap in the tree to turn into high pressure steam and the tree literally explodes. Lightning rods connected to heavy cables are mounted on top of tall buildings in lightning country, to provide a safe path for the electricity to discharge to ground. If the lightning discharges through the building, the heat from the current flow could cause the building to burn. Clouds are made when water molecules in warm, humid air slow down as the air is cooled.