If you have been following this blog, you now know that we are in hurricane season. Although there currently is no tropical activity it could pop up at any time. According to NOAA “the greatest potential for loss of life related to a hurricane is from the storm surge.”
Storm surge is simply water that is pushed toward the shore by the force of the winds swirling around the storm. This advancing surge combines with the normal tides to create the hurricane storm tide, which can increase the mean water level 15 feet or more. In addition, wind-driven waves are superimposed on the storm tide. This rise in water level can cause severe flooding in coastal areas, particularly when the storm tide coincides with the normal high tides. Because much of the United States’ densely populated Atlantic and Gulf Coast coastlines lie less than 10 feet above mean sea level, the danger from storm tides is tremendous.
This is where things could get worse in the Gulf of Mexico. Currently the oil spill is pretty much stalling at the shore line or the beginning of wetlands. That is NOT a good thing but it could be worse. What if the storm surge from a hurricane pushed the spill further inland, further into the estuaries and even up the Mississippi River. One can only imagine the devastation that might cause.
The level of surge in a particular area is also determined by the slope of the continental shelf. A shallow slope off the coast (graphic to the right) will allow a greater surge to inundate coastal communities. Communities with a steeper continental shelf (bottom graphic) will not see as much surge inundation, although large breaking waves can still present major problems.
Storm tides, waves, and currents in confined harbors severely damage ships, marinas, and pleasure boats.
Wave and current action associated with the tide also causes extensive damage. 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 currents created by the tide combine with the action of the waves to severely erode beaches and coastal highways. Many buildings withstand hurricane force winds until their foundations, undermined by erosion, are weakened and fail.
In estuaries and bayous, intrusions of salt water endanger the public health and send animals, such as snakes, to flee from flooded areas and take refuge in urban areas.