Characteristics of Storm Surges

By Jeffrey Masters, Ph.D. — Director of Meteorology, Weather Underground, Inc.

Figure 1. Storm surge along gently sloping (left) and steeply sloping shoreline (right). A larger surge occurs on the gently sloping shore; the steeply sloping shore has higher waves on top of the surge. The source of this material is the COMET© Website at http://meted.ucar.edu/ of the University Corporation for Atmospheric Research (UCAR), sponsored in part through cooperative agreement(s) with the National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce (DOC). ®1997-2009 University Corporation for Atmospheric Research. All Rights Reserved.

  • The highest surges usually occur to the right of the storm track (traveling with the storm) at approximately the radius of maximum wind.
  • Fast moving storms cause high surges along open coast and lower surges in sheltered bays and estuaries.
  • Slow moving storms usually result in greater flooding inside bays and estuaries, with smaller values along the open coast.
  • Larger storms affect longer stretches of the coastline. A larger storm is defined as a storm having a greater radius of maximum wind.
  • Storms with larger eyes create larger surges, up to an eye diameter of about 30 miles.
  • The direction of storm approach often impacts the extent of flooding.
  • Depending on location, storms from one direction may cause inundation, while a storm of the same magnitude from a different direction may cause little flooding.
  • The slope of the near-shore seabed will affect the level of surge in a particular area. Areas with shallow continental shelf slopes will allow a greater storm surge, but have smaller waves. For example, on the Gulf Coast of Florida, the edge of the shallow water (depth less than 300 feet) "Floridan Plateau" lies more than 100 miles (160 km) offshore of Marco Island in Collier County. As a result, Marco Island can receive a storm surge of 22 - 24 feet in an west-to-east moving Category 5 hurricane.
  • Areas with deep water just offshore experience large waves, but little stormsurge. Miami Beach, Florida is a good example of this. The maximum storm surge from a Category 5 hurricane is 8 feet, for a east-to-west moving storm. This is a factor of 3 to 4 less than the typical maximum surge possible elsewhere on the U.S. Atlantic Coast. The edge of the Floridan Plateau, where the water depths equal 300 feet, lies just 2 miles (3 km) offshore of Palm Beach, Florida. Just 4 miles (7 km) offshore, the depth plunges to over 180 meters.

Weather Underground Storm Surge Articles

Storm Surge Safety Actions

  • Minimize the distance you must travel to reach a safe location; the further you drive the higher the likelihood of encountering traffic congestion and other problems on the roadways.

  • Select the nearest possible evacuation destination, preferably within your local area, and map out your route. Do not get on the road without a planned route, or a place to go.

  • Choose the home of the closest friend or relative outside a designated evacuation zone and discuss your plan with them before hurricane season.

  • You may also choose a hotel/motel outside of the vulnerable area.

  • If neither of these options is available, consider the closest possible public shelter, preferably within your local area.

  • Use the evacuation routes designated by authorities and, if possible, become familiar with your route by driving it before an evacuation order is issued.

  • Contact your local emergency management office to register or get information regarding anyone in your household whom may require special assistance in order to evacuate.

  • Prepare a separate pet plan, most public shelters do not accept pets.

  • Prepare your home prior to leaving by boarding up doors and windows, securing or moving indoors all yard objects, and turning off all utilities.

  • Before leaving, fill your car with gas and withdraw extra money from the ATM.

  • Take all prescription medicines and special medical items, such as glasses and diapers.

  • If your family evacuation plan includes an RV, boat or trailer, leave early. Do not wait until the evacuation order or exodus is well underway to start your trip.

  • If you live in an evacuation zone and are ordered to evacuate by state or local officials, do so as quickly as possible. Do not wait or delay your departure, to do so will only increase your chances of being stuck in traffic, or even worse, not being able to get out at all.

  • Expect traffic congestion and delays during evacuations. Expect and plan for significantly longer travel times than normal to reach your family's intended destination.

  • Stay tuned to a local radio or television station and listen carefully for any advisories or specific instructions from local officials. Monitor your NOAA Weather Radio.

Source: NOAA

Hurricane Preparedness

National Hurricane Center

Centers for Disease Control & Prevention