Understanding Storm Surges – How a Storm Surge Works
By Joe Tracy, Publisher of NEWSdial.com

Few people realize that the most damage from a hurricane doesn’t come from the high winds and rain, but rather from the storm surge that generally accompanies a hurricane.

A storm surge is much like a tsunami in that a large surge of water leaves the ocean and journeys upon land. The storm surge is caused by the force of the swirling hurricane, low pressure, and tide levels. When you vacuum a floor you notice that the carpet gets sucked up in the area you are vacuuming. Likewise, low pressure from a hurricane lifts the ocean water level then the high winds push that water. As the hurricane gets closer to land, the surges get more intense.

This is where tide comes in. Let’s say that a hurricane’s impact on the ocean has created a 15-foot storm surge. Now, let’s say at the time the hurricane is approaching land, it is high tide, and the ocean is two feet above normal. Combined with the surge, the ocean is now 17 feet above level, flooding anything its path.

One final factor that determines the destructive nature of a storm surge is the slope of the land. Smooth rising slopes are much more dangerous for a continuing destructive push of water than bigger cliff-like drop offs. See the animated gif to the right for an example (Figure 1).

Here’s how the National Oceanic & Atmospheric Administration (NOAA) describes storm surges:

“Storm surge is simply water that is pushed toward the shore by the force of the winds swirling around the storm. This advancing surge combines with the normal tides to create the hurricane storm tide, which can increase the mean water level 15 feet or more. In addition, wind driven waves are superimposed on the storm tide. This rise in water level can cause severe flooding in coastal areas, particularly when the storm tide coincides with the normal high tides. Because much of the United States' densely populated Atlantic and Gulf Coast coastlines lie less than 10 feet above mean sea level, the danger from storm tides is tremendous.”

Before a lot of information was known about storm surges, up to 90% of deaths in hurricanes were a result of these surges. The ability to educate the public about storm surges has resulted in more people being aware, cautious, and evacuating at the appropriate time. Like a tsunami, storm surges wipe out a large amount of human lives who are within its path. However, unlike tsunami’s, storm surges are created by surface events versus underwater events. The key is to not be in the path of a storm surge and to heed evacuation orders. Things can be replaced. People can’t.

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