Question: What is a Storm Surge?
A storm surge occurs when water is pushed inland as a result of high winds. Coastal zones are particularly at risk for storm surges. While typically associated with tropical cyclone (hurricanes, typhoons, and cyclones) a storm surge can also occur when abnormally high winds combine with a high tide. Calculation of storm surge heights are usually subtracted from the normal tide heights.
Answer:
How is a Storm Surge Different from a High Tide?
The storm surge resulting from a hurricane is one of the more deadly portions of a storm. Think of a storm surge as a giant bulge of water. Much like in a bathtub, waves of water can slosh back and forth in a tub. Earth's oceans are like a giant bathtub. Normal water levels rise and fall in periodic and predictable ways due to the gravitational attractions between the Earth, sun, and moon. We call these tides. However, the low pressure of a hurricane combined with high winds causes the normal water levels to rise. Even high and low tide waters can rise beyond their normal levels.
Why are Some Areas More Prone to Storm Surge Damages?
Depending on the geography of the coast, some areas are more susceptible to storm surge damages. For example, if a continental shelf is gently sloping, the power of a storm surge can be greater. A steep continental shelf will cause the storm surge to be less intense. In addition, low lying coastal areas are often at risk of increased flood damage.Some areas also act as a sort of funnel through which water can surge even higher. The Bay of Bengal is one location where water is literally funneled into the coast. In 1970, a storm surge killed at least 500,000 people in the Bhola cyclone. In 2008, the shallow continental shelf in Myanmar caused Cyclone Nargis to produce intense storm surges killing tens of thousands of people. (Go to a video explaining the Myanmar storm surge.) The Bay of Fundy, while not usually hit by hurricanes, experiences tidal bores daily due to its funnel shaped land structure. While not caused by a storm, a tidal bore is an increased surge of water from tides due to the geography of an area. The 1938 Long Island Express hurricane caused extensive damage as it hit New England and threatened the Bay of Fundy. But by far the greatest damage was done by the Saxby Gale hurricane of 1869.
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