|Louisiana Coast is warm and humid
with annual rainfall amounts between 40 and 70 inches. Rainfall generally
comes in the form of large storms, so annual rates are dependent on weather
anomalies such as El Nino. Extratropical storms in the winter and
thunderstorms and tropical storms in the summer and fall supply most of the
precipitation. Tropical storms hit Louisiana coastal wetlands approximately
every 4 years. Hurricanes have a much less predictable pattern.
Monthly precipitation varies from July being the wettest and October
The Louisiana Coast is at approximately 30 degrees North latitude, and
during the summer the peak solar insolation of 600 calories/square centimeter
represents the highest solar insolation on the planet. Because of this,
the growth potential during the summer is the best in the world. Mean
temperatures tend to follow insolation closely, resulting in winter temperatures
averaging 14 degrees Celcius and summer temperatures reaching 30 degrees
Celcius. The massive volume of water present in the wetlands creates
a moderating effect, keeping the summers very hot and humid. Frost
is infrequent with an average of less than 50 days with frost risk annually.
Water temperatures in the wetlands are closely related to air temperatures
due to the low volume to surface area ratio.
|Mean precipitation in
Mean temperature in Louisiana
Impacts of Hurricane
Andrew on coastal wetlands
Andrew was a relatively small hurricane but when it came ashore on August
26th, 1992, it hit the Louisiana Coastal wetlands hard. Wind gusts
of 169 mph and over 7 inches of rain resulted in a storm surge of 9ft.
Despite the huge storm surge, little coastal flooding occurred. Nearly
80% of the trees in some coastal forests were knocked down. The heavy
wave action caused resuspension of toxic anaerobic soils, which killed
182 million freshwater fish in the Atchafalaya River basin alone.
The floating marsh mats were the most damaged through physical movement
due to wind and wave action. Other sections of the marsh were damaged