Two reasons: strong winds and storm surge (the crashing of waves inland). So to understand the answer to this question, you first need to know what causes wind and waves. Temperature differences in the atmosphere create changes in air pressure. Wind is the movement of air from areas of high to low atmospheric pressure. Waves, meanwhile, are created by wind blowing over a body of water. Those tube-shaped ‘’barrels’’ that surfers ride off the north shore of Hawaii? They were created by wind blowing on the ocean’s surface thousands of miles away.
Now, hurricanes typically take shape over tropical oceans and coasts, where the warm ocean waters create an area of low pressure in the moist air. Bundles of thunderstorms form, fueled by the warm ocean temps and whipped into a swirling shape by the Earth’s rotation and growing wind. What starts as a ‘’tropical depression’’ becomes a ‘’tropical storm’’ when the winds reach 39 mph (63 kph). When the winds top 74 mph (119 kph), the storm is officially declared a hurricane.
Hurricane winds can reach 150 mph (241 kph), tearing apart houses and tossing cars. When these massive storms hit land, they bring flooding rain and sometimes spawn tornadoes. Even if a hurricane never makes landfall, its wind can create massive waves three stories high that crash ashore as deadly storm surge.
Picture Credit : Google