On the last day of this hurricane preparedness week, we have to highlight the deadliest threat a storm can bring. Of course, storm surge is not experienced by inland residents, but with many more living on the coast, it is often a storm's most catastrophic threat. Storm surge is a hurricane’s deadliest threat. Do you know how to stay safe when it threatens your area?
In 2021 Hurricane Ida made landfall in Louisiana and caused up to 12 feet of storm surge for some locations. This left cars and properties damaged. Ian was notorious for its storm surge. The final trajectory brought a storm surge of at least 13.8 feet in Fort Myers Beach. This was the highest surge ever recorded in Southwest Florida's history of 150 years. For reference, Hurricane Charley produced half of the surge in the same area in 2004. That's because Charley was a tiny storm in size.
Florida's elongated shape puts it at great risk even when a storm doesn't necessarily hit the state directly.
Run from the water, hide from the wind
In 2005, Hurricane Katrina slammed into southeastern Louisiana. Storm surge combined with a failed levee system resulted in the death of at least 1,500 people. Some portions of the coast observed inundation up to 28 feet!
What is storm surge?
Storm surge is an abnormal rise of ocean water generated by an approaching low-pressure system, often a hurricane. As the storm nears the coast, water is pushed onshore by its strong winds. The inundation causing storm surge, which could be several feet high, is measured above the local astronomical tide.
Several factors can make a storm surge more susceptible than others. One of these is, of course, storm intensity. Stronger storms have higher winds that can exert more force over the ocean, pushing more water inland.
Another factor is bathymetry and the continental shelf. The shape and slope of the ocean bottom can have a significant effect on storm surge. For example, water that is pushed towards the coast can ride inland easier over a shallow slope versus a steep one.
Other factors that can influence storm surge are storm forward speed, angle of approach to the coast, central pressure, and the shape and characteristics of coastal features such as bays and estuaries.
Forecasting storm surge
With so many moving parts, it can become quite challenging to pinpoint precisely how much storm surge an area may experience in the event of a hurricane or strong low-pressure system.
Meteorologists at the National Hurricane Center use the Sea Lake and Overland Surge from Hurricanes (SLOSH) model that considers all the factors mentioned above to predict how much inundation an area may experience.
Staying safe from coastal inundation
The best way to prepare for storm surge is to understand your risk. If you are near the coast or in a low-lying area, you are more likely at risk of storm surge and should closely monitor the progress of storms. If you are in an evacuation zone and prompted to leave, it is a good idea to heed and follow guidance from your local authorities.
Remember, storm surge is just one piece of the puzzle. Heavy rain can make inundation in your area worse, while battering waves above the surge may increase damage to buildings directly along the coast.