Damage-Causing Winds
Hurricanes produce damaging surface winds and storm surges. While high winds cause significant structural and environmental damage, storm surges are frequently the most devastating element of a hurricane.
Storm Surges
A storm surge is a rise in sea level along a coastline caused by the combination of a hurricane's surface winds and the physical geography of a coastline. Surface winds above the ocean's surface push water toward the hurricane's eye, creating a mound of water. The mound of water is then influenced by the slope of the coastline as the hurricane approaches land. If the coastline is shallow, water cannot flow away from the mound and the mound grows. If the coastline is deep, water can disperse and the mound may grow slowly or disperse depending on hurricane strength. An example of a shallow-water coastline is the Gulf Coast while an example of a deep-water coastline is found in New England.
Shallow-water Coastline
Deep-water Coastline
Each of the animations above depicts surge dynamics in action. As you watch the storm-surge animations, notice the effect that the physical geography of each coastline has on storm surge. Also note the waves on top of the ocean's surface. Wind, waves, and sea-level rise all contribute to storm-surge damage
The greatest storm-surge damage is to the right of a hurricane's eye (as you face the shoreline) in the Northern Hemisphere. It occurs to the right of the eye because winds, ocean waves, and sea-level rise are all moving in an onshore direction. In contrast, to the left of the eye, ocean waves and sea-level rise are moving in an onshore direction, but the winds are blowing in an offshore direction. The offshore direction of the winds moderates the effect of the storm surge. You will explore this idea in the Explore Hurricanes section with Hurricane Opal as it comes ashore.
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