There are five types of hurricane damage, four of which occur in Hawaii. The first damage to occur from a hurricane is from storm surge. Storm surge is a large mound of water which can be fifty to one hundred miles wide that sweeps across the coastline near a hurricane's landfall. This dome of water topped by waves is powerfully destructive. The stronger the hurricane combined with shallower offshore water will increase the height of the storm surge. The worst coastline damage is caused by storm surge and can actually be the worst part about a hurricane.
The occurence of storm surge with the arrival of high tide can cause a second type of damage. This is known as storm tide. Storm tide is the combination of storm surge and the normal astronomical type. An example of this is when a 15-foot storm surge arrives with a 2-foot tide, creating a 17-foot dome of water.
Storms are classified as hurricanes when sustained winds reach 74 mph or more. Winds of this intensity can shatter poorly constructed structures. Signs, roofing material, siding, and other debris can become deadly flying objects. Downed trees and power lines can block roadways, making rescue efforts difficult. Power can be lost for days and even weeks at a time. When Hurricane Iniki struck Kauai, only 20% of the island had regained power four weeks following the storm.
Heavy rains and floods can be another destructive consequence of hurricanes. In fact, a modified hurricane-classification system is being considered because several recent hurricanes, while not being above Category 3, have produced horrendous flooding.
The last type of damage can be caused by tornados spawned during hurricanes. While Hawaii does not experience this kind of damage, most hurricanes do produce mini-downbursts of wind similar in nature to tornados, known as microbursts. The wind intensity of microbursts can far exceed the measured sustained winds of the hurricane.
Damage of Hurricane Iniki