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Storm surge, the deadliest threat from tropical cyclones

NOAA storm surge hazard maps have expanded coverage and can help you stay safe
May 10, 2019

When people hear about hurricanes most immediately think of high winds. But it’s the water that’s responsible for nearly 90% of fatalities – and half of those are due to storm surge. Do you know if you’re at risk?

Hurricane Michael made landfall near Mexico Beach, Florida on October 10, 2018. The category 5 hurricane came ashore with 160 mph winds and strong storm surge.

Thanks to improved computer modeling, several years of experimentation, and social science research, NOAA’s National Hurricane Center has an interactive web tool, the National Storm Surge Hazard Maps to help you find out. The first version was issued in 2014 and covered the U.S coastline from Texas to Maine. Puerto Rico was added in 2017. This year the system has expanded to include the Hawaiian Islands, U.S. Virgin Islands, and Hispaniola.

These storm surge hazard mapsoffsite link enable people living in hurricane-prone coastal areas to evaluate their risk of coastal flooding due to storm surge. And don’t forget, storm surge is not just a beachfront problem. The hazard extends many miles inland from the immediate coastline in some areas. Understanding this risk gives you the time to take action when emergency managers tell you to evacuate.

These interactive maps show areas of storm surge flooding vulnerability. It helps people living in hurricane-prone areas evaluate their risk to the hazards of storm surge.
These interactive maps show areas of storm surge flooding vulnerability. It helps people living in hurricane-prone areas evaluate their risk to the hazards of storm surge. (NOAA/Esri)

One of the key components in developing this tool is a computer model appropriately named SLOSH, the Sea, Lake, and Overland Surges from Hurricanes. Scientists at the hurricane center use SLOSH to simulate hundreds of thousands of hypothetical hurricanes and the potential storm surges are calculated.

Composites of the resulting storm surges are created and high-resolution inundation maps are created using local topography.  In locations that have a steep and narrow continental shelf, such as islands, waves can be a substantial contributor to the total water level rise observed during a tropical cyclone.  For these areas, SLOSH has been coupled with a wave model to enable a more complete and accurate analysis of flood risk.

If you live in or visit a location that may be affected by a tropical cyclone, know the hazards ahead of time and have a hurricane plan in place to implement at a moment’s notice. For more information visit NOAA’s National Hurricane Center.

Storm surge safety tips, in English - in Spanish