What is Storm Surge?
Storm surge is the very fast, abnormal rise in seawater level during a storm, measured as the height of the water above the normal predicted astronomical tide. The surge is caused primarily by a storm’s winds pushing water onshore. The size, speed and volume of the surge of rushing ocean water at any given location depends on a complicated series of factors. Learn more here from the National Ocean Center or here from the National Hurricane Center.
Storm Surge Fast Draw
Meanwhile, know that more hurricane and tropical storm deaths are attributable to drowning in storm surge than any other factor. It can’t be outrun or outdriven; if evacuation orders are issued to you, leave without delay.
Storm Surge Is Serious; Be Prepared
Storm surge is a deadly, damaging force that comes with many coastal storms—from sub-tropical storms to hurricanes to nor’easters. Storm surge respects neither seasons nor boundaries. The following guidance could save your life or someone else’s.
- Storm surge poses a significant threat for drowning and property damage. Even just six inches of fast-moving water can knock you off your feet, and just two feet will carry away even trucks and SUVs.
- Take action and GO when an evacuation is ordered for your area. You cannot outrun or outdrive the incredible speed and power of storm surges. Know (find out today) if you are in a storm surge evacuation zone, and what route to take to safety. Always remember that evacuation routes can be cut off by storm surge in a matter of minutes.
- Storm surge can be a risk in ANY strong coastal storm in ANY season. Rely on local officials to guide your decisions; do NOT rely on your past experience with storms. Many details—tides, winds, size and speed of storm, and other factors—are used to measure storm surge risk to keep you and your family safe. Heed warnings.
- Both the Atlantic and Gulf coasts are vulnerable to storm surge, which can impact areas several miles inland as marshes, rivers and other areas become inundated with fast-moving waters.
- If you can’t get out, emergency responders can’t get in during surge conditions. Evacuate so you don’t put other lives in danger.
For additional information, please visit the National Hurricane Center’s Tips for Storm Surge.
Storm Surge Survival Misconceptions
The storm surge is usually the most dangerous threat of a hurricane. Those lucky enough to survive Hurricane Katrina’s record storm surge shared their stories, shedding light on some common misconceptions about storm surge survival.
Misconception: Call 911 and you can be rescued, while the water is pouring into your home.
How? No one will be able to get to you. Water rises quickly—sometimes 6-10 feet within minutes; cars can’t drive in it and it is usually unnavigable by boats when it is coming ashore.
Misconception: Just stuff towels under the door jambs. Then rush around to start picking up things that are close to floor level, so you can save them.
Bad idea. In a minute or so the surge will burst open the door, and instead of standing in a room with four inches of water, you’ll be knocked off your feet and into whatever piece of furniture is closest. You’ll suddenly be in three or four feet of moving water that you can’t make any headway into.
Misconception: You’ll be able to maneuver around in the rushing water.
Probably not. Some people who drowned were not even able to get out of the room they were in when the water started pouring into the home. The speed of water in a surge can be equivalent to Class III or IV rapids (Class V is hardly navigable even by expert kayakers).
Misconception: You’ll know in time.
The surge is usually not a wall of water as is often assumed but rather a rapid rise of water of several feet over a period of minutes, meaning it can sneak in unexpectedly.
Misconception: You can outrun the storm surge in your car.
If you wait until the water is an inch high before trying to outrun the surge, the odds are that the surge will rise to over a foot high before you get your car out of the driveway. If the water is a foot high, the typical 10-15 mph speed of the storm surge’s current has enough force to sweep a car away. In many places along the coast such as the Keys, there is only one road out of a low-lying region prone to storm surges. In such cases, the storm surge will likely be moving perpendicular to the road, cutting off the only escape route.
Storm Surge Location Facts
- From 1990-2008, population density increased by 32% in Gulf coastal counties, 17% in Atlantic coastal counties, and 16% in Hawaii (U.S. Census Bureau 2010)
- Much of the United States’ densely populated Atlantic and Gulf Coast coastlines lie less than 10 feet above mean sea level
- Over half of the Nation’s economic productivity is located within coastal zones
- 72% of ports, 27% of major roads, and 9% of rail lines within the Gulf Coast region are at or below 4 ft elevation (CCSP, SAP 4-7)
- A storm surge of 23 ft has the ability to inundate 67% of interstates, 57% of arterials, almost half of rail miles, 29 airports, and virtually all ports in the Gulf Coast area (CCSP SAP 4-7)