Storm surge is often the greatest threat to life and property along the coast during and after a hurricane.
A number of deaths from major hurricanes have resulted from the ocean’s rise due to storm surge. Hurricane Katrina, which made landfall near New Orleans in 2005, was a prime example of how surge can cause damage and destruction. Some 1,500 people lost their lives during Katrina and many of those deaths occurred directly and indirectly from storm surge.
More recently, onshore winds from Hurricane Helene in 2024 produced record storm surge levels and coastal flooding along the western Gulf Coast of Florida. Major flooding, debris and damages to structures were observed from the Keys north to Florida’s Big Bend region.
In Florida’s Big Bend region, where the Category 4 Helene inflicted its wrath, storm surge inundation of 12 to 16 feet above ground level occurred from just west of Keaton Beach through Steinhatchee, where small coastal communities were devastated. Helene was responsible for 176 fatalities in the U.S. In Florida, 14 deaths were caused by storm surge, according to NOAA.
“Know your risk from storm surge. This includes knowing how high the elevation of the ground is outside (or under) your home,” said Jon Rizzo, warning coordination meteorologist for National Weather Service Key West. “One clear rule of thumb for those living on the lowest ground in the Keys is from this question: Have you observed king tide, or sunny day’ flooding typically in autumn on your street or property? If that answer is ‘yes’ you are living on the lowest elevations in the Keys and will be most at risk for devastating storm surge.”
What influences surge?
The larger the storm, the higher the surge. This is due to stronger winds from larger storms pushing onto a larger area of the ocean. Those winds will stay around longer due to the storm’s size. The angle at which a storm approaches a coastline, winds and slope of the ocean bottom and coastline shape also contribute to surge from a given storm.
On the open coast, a faster storm will produce a higher surge. And higher surge is produced in bays, sounds and other enclosed bodies of water with a slower storm.
Watches versus warnings
Look out for storm surge watches and warnings. A storm surge watch indicates the possibility of life-threatening, rising water moving inland from the shoreline within a specified area, generally within 48 hours of a storm’s arrival. The watch may be issued earlier when other conditions, such as the onset of tropical storm-force winds, are expected to limit the time available to take protective actions for surge (e.g., evacuations).
A storm surge warning is the likelihood of life-threatening water that’s rising and moving inland from the shoreline within a specified area within 36 hours of a storm’s arrival. A warning could be issued earlier when other conditions such as the onset of tropical storm force winds are expected to limit the time available to take protective actions for surge, like evacuations.
Take evacuation orders seriously
Storm surge evacuation orders from local emergency management officials should be heeded immediately. “Storm surge can cause water levels to rise quickly and flood large areas sometimes in just minutes, and you could be left with no time to take action if you haven’t already evacuated as instructed,” says the Florida Division of Emergency Management.
If you are not sure of the elevation of your neighborhood, the National Storm Surge Hazard Maps may help: nhc.noaa.gov/nationalsurge. This interactive tool displays the maximum storm surge each category of hurricane may produce as the potential depth of water over ground level.
