A Brief Climatology of Tropical Cyclones
in Louisiana

Statistics.  Some of the most deadly tropical storms and hurricanes to ever hit the United States have struck the shores of Louisiana. Memorable storms include Andrew in 1992, Camille in 1969, Betsy in 1965, Audrey in 1957, the August Hurricane of 1940, the September Hurricane of 1915, the Cheniere Caminanda Hurricane of 1893, the Isle Dernieres Hurricane of 1856, and the Racer's Storm of 1837. These storms claimed as many as 3000 lives from the Pelican state, with Audrey claiming the highest death toll in  in modern times, with 526 lives lost from Cameron and nine in Texas.

On average, since 1871, a tropical storm or hurricane should be expected somewhere within the state every 1.2 years.  A hurricane should make landfall every 2.8 years. On the following table is a list of the number of tropical storm and hurricanes that have adversely affected Louisiana per decade, since 1851:
 

Louisiana has few barrier islands; therefore, the problem of overpopulation slowing down evacuation times, e.g. Florida, does not exist. New Orleans has high evacuation times due to a relative lack of major highways out of the city and dense population...I-10 is pretty much the only route of escape. But we do have our own unique problems. A lack of coastal irregularities and a general smooth Gulf of Mexico bottom make Cameron Parish ideal for maximum wave damage along its shores (Morgan). The land in lower sections of Southern Louisiana is slowly sinking and at the same time, quickly eroding away.  In some places, the loss can be as much as a foot a year!

The construction of levees around the Mighty Mississippi over the centuries has led to a rise in the level of the river, which could make a crevasse through the river not merely a nuisance, but a life-threatening fact of life.  Each increase of the height of the river multiplies the havoc that could ensue if a break should occur in its banks.  Back in 1718, the levees were only three feet high; today they are 17 feet high.

Pressure.  The stronger a hurricane gets, the lower its central pressure gets.  It is a direct relationship.  Below is a table showing the lowest ten pressures ever recorded across Louisiana since the Nineteenth Century.
 

Winds.  Major hurricanes have led to massive devastation through the years.  Extreme structural damage is noted with storms of category three intensity of higher (winds of 111 mph and above).  Below is a chart showing the highest wind gusts measured across the Bayou State over the years.
 

Storm Surge.  Storm surge flooding across southeast Louisiana is greater than surrounding areas due to it orientation of being a "corner" along the Gulf coast.  This means that the approximate angle made by the Mississippi Delta with the rest of the Gulf coast is nearly ninety degrees, which would amplify the piling up of water with an east wind.  In this case, Lakes Pontchartrain and Borgne are the targets.  Another similar "corner" along the U.S. coastline is New York City.

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