Hurrican Shutters

Installing "Peace of Mind"

Storm Surge Overview from National Hurricane Center

Posted by cat5shuttersllc on February 21, 2012

Storm Surge Overview from National Hurricane CenterAlong the coast, storm surge is often the greatest threat to life and property from a hurricane. In the past, large death tolls have resulted from the rise of the ocean associated with many of the major hurricanes that have made landfall. Hurricane Katrina (2005) is a prime example of the damage and devastation that can be caused by surge. At least 1500 persons lost their lives during Katrina and many of those deaths occurred directly, or indirectly, as a result of storm surge.

Storm Surge vs. Storm Tide

Storm surge is an abnormal rise of water generated by a storm, over and above the predicted astronomical tides. Storm surge should not be confused with storm tide, which is defined as the water level rise due to the combination of storm surge and the astronomical tide. This rise in water level can cause extreme flooding in coastal areas particularly when storm surge coincides with normal high tide, resulting in storm tides reaching up to 20 feet or more in some cases.

Storm Surge vs. Storm Tide

Factors Impacting Surge
Storm surge is produced by water being pushed toward the shore by the force of the winds moving cyclonically around the storm. The impact on surge of the low pressure associated with intense storms is minimal in comparison to the water being forced toward the shore by the wind.

Wind and Pressure Components of Hurricane Storm Surge

The maximum potential storm surge for a particular location depends on a number of different factors. Storm surge is a very complex phenomenon because it is sensitive to the slightest changes in storm intensity, forward speed, size (radius of maximum winds-RMW), angle of approach to the coast, central pressure (minimal contribution in comparison to the wind), and the shape and characteristics of coastal features such as bays and estuaries.

Other factors which can impact storm surge are the width and slope of the continental shelf. A shallow slope will potentially produce a greater storm surge than a steep shelf. For example, a Category 4 storm hitting the Louisiana coastline, which has a very wide and shallow continental shelf, may produce a 20-foot storm surge, while the same hurricane in a place like Miami Beach, Florida, where the continental shelf drops off very quickly, might see an 8 or 9-foot surge. More information regarding storm surge impacts and their associated generalizations can be found in the FAQ section.

Adding to the destructive power of surge, battering waves may increase damage to buildings directly along the coast. Water weighs approximately 1,700 pounds per cubic yard; extended pounding by frequent waves can demolish any structure not specifically designed to withstand such forces. The two elements work together to increase the impact on land because the surge makes it possible for waves to extend inland.

Although elevated, this house in North Carolina could not withstand the 15 ft (4.5 m) of storm surge that came with Hurricane Floyd (1999) Hurricane Floyd 1999
Additionally, currents created by tides combine with the waves to severely erode beaches and coastal highways. Buildings that survive hurricane winds can be damaged if their foundations are undermined and weakened by erosion.

Beachfront road and boardwalk damaged by Hurricane Jeanne (2004)
In confined harbors, the combination of storm tides, waves, and currents can also severely damage marinas and boats. In estuaries and bayous, salt water intrusion endangers the public health, kills vegetation, and can send animals, such as snakes and alligators, fleeing from flooded areas.

Notable Surge Events
  • Ike 2008
  • Katrina 2005
  • Dennis 2005
  • Isabel 2003
  • Opal 1995
  • Hugo 1989
  • Camille 1969
  • Audrey 1957
  • New England 1938
  • Galveston 1900
Surge Vulnerability Facts
  • From 1990-2008, population density increased by 32% in Gulf coastal counties, 17% in Atlantic coastal counties, and 16% in Hawaii (U.S. Census Bureau 2010)
  • Much of the United States’ densely populated Atlantic and Gulf Coast coastlines lie less than 10 feet above mean sea level
  • Over half of the Nation’s economic productivity is located within coastal zones
  • 72% of ports, 27% of major roads, and 9% of rail lines within the Gulf Coast region are at or below 4 ft elevation (CCSP, SAP 4-7)
  • A storm surge of 23 ft has the ability to inundate 67% of interstates, 57% of arterials, almost half of rail miles, 29 airports, and virtually all ports in the Gulf Coast area (CCSP SAP 4-7)
Hurricane Storm Protection

Property owners along the Gulf of Mexico and Atlantic Ocean should strongly consider installing hurricane shutters. Category 5 hurricanes can result in structural damages in excess of 15 miles from the shore. Cat 5 hurricane shutters are recommended for all regions close to the shore. Contact Cat 5 Shutters for all your hurricane protection products and needs.

Distributed by Viestly

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