NOAA: National Oceanic and Atmospheric Administration
Storm Surge and Coastal Inundation
Storm surge headed ashore.A view of levee repairs following the storm surge damage from Hurricane Katrina - 2005Wind-driven waves and storm surge threaten to inundate homes in Miami, Florida - 1945Treasure Bay Casino (Biloxi, MS) was moved completely off its moorings by the storm surge from Hurricane Katrina - 2005Views of inundated areas in New Orleans following breaking of the levees surrounding the city as the result of storm surge from Hurricane Katrina - 2005House in North Carolina damaged by 15-foot storm surge that came with Hurricane Floyd - 1999Venice, LA, still with at least two to three feet of water two weeks after Hurricane Katrina's storm surge - 2005Huge waves from Hurricane Carol's storm surge destroyed hundreds of beach front cottages and homes in Connecticut - 1954
Hard Rock Casino barge (Biloxi, MS) completely destroyed during Hurricane Katrina - 2005Coast Guard surf boat ploughing through.Views of inundated areas in New Orleans following breaking of the levees surrounding the city as the result of storm surge from Hurricane Katrina - 2005Damage to manufactured and mobile homes at Surfside Beach, SC, after Hurricane Hugo's storm surge - 1989Damage caused by the Galveston Hurricane and storm surge: the greatest natural disaster in terms of loss of life in U.S. history (6,000 to 8,000 individuals died in this event) - 1900Damage to beach front homes on Dauphin Island, AL, due to storm surge from Hurricane Katrina - 2005Storm surge from Hurricane Carol lashes Rhode Island Yacht Club - 1969A view of levee repairs following the storm surge damage from Hurricane Katrina - 2005-----



Storm Surge

Preparing coastal communities for storm surge flooding

What is storm surge and coastal inundation?

Storm surge is one of the main causes of coastal inundation. Storm surge is the abnormal rise in water level, over and above the regular astronomical tide, caused by a severe storm such as a tropical cyclone or nor'easter. Large waves also raise coastal water levels and ride on top of the storm surge to cause extreme damage.

Coastal inundation is the flooding of normally dry, low-lying coastal land, primarily caused by severe weather events along the coasts, estuaries, and adjoining rivers. These storms, which include hurricanes and nor’easters, bring strong winds and heavy rains. The winds drive large waves and storm surge on shore, and heavy rains raise rivers. (A tsunami – a giant wave caused by earthquakes or volcanic eruptions under the sea or landslides into the sea – is another kind of coastal inundation, but should not be confused with storm surge.)

Storm surges are extremely dangerous because they are capable of flooding large coastal areas, causing severe devastation.

To prevent disaster, avoid the water and waves, and when local authorities instruct you to evacuate, do so quickly!

If you are currently experiencing a storm surge event, visit your local National Weather Service weather forecast office website for information about local surge impacts under coastal flood watches or warnings and hurricane local statements:

“What areas are vulnerable to coastal inundation?”

All low-lying coastal regions, which can cover tens of miles inland, are vulnerable to flooding from storms, and the impact can be substantial.

"When I visit with citizens who have Bill Readexperienced a land falling hurricane,
I am frequently told 'I had no idea storm surge could happen to me.'"

Bill Read, Former Director
NOAA National Hurricane Center

“What kind of damage does storm surge do?”

Storm surge, associated with many major hurricanes and extratropical storms, can cause many deaths and devastating property loss. Storm surges have damaged roads and bridges, destroyed homes and businesses, and wiped out entire coastal communities. Hurricane Katrina (2005) is a prime example of the damage and devastation that is possible. At least 1500 people lost their lives during Katrina, and many of those deaths occurred because of storm surge, either directly or indirectly. Katrina also caused well over $100 billion in damage from its surge and winds.

“Can storm surge be predicted?”

Yes, advanced computer models are used to simulate the weather conditions in a severe storm to learn how it can cause coastal inundation conditions. The SLOSH (Sea, Lake, and Overland Surges from Hurricanes) model simulates surge from tropical storms to predict potential storm surge impact. NOAA has several models, such as an extratropical storm surge model, that predicts surge and its impact from extratropical storms.

“How do I know if coastal inundation from a storm will affect me?”

NOAA's National Weather Service monitors coastal inundation conditions 24 hours a day, 7 days a week. The Weather Service issues forecasts, watches, and warnings, with details on a storm's impact. Local emergency management officials use this information to decide when evacuations are necessary, and if they are, report them to media outlets. Keep track of the information provided by your local weather forecast office and listen to local media reports.

“What can I do to protect my family and property from potential storm surge?”

Be prepared. Know the hazards that may affect you, your family, and your home. Make plans for where you’ll go if told to evacuate. Have a disaster supply kit within reach. Stay tuned to local radio and television stations, and listen for advisories or specific instructions from your local officials. Monitor your NOAA weather radio.

Along the coast, storm surge is often the greatest threat to life and property from a tropical or extratropical storm.