Tuesday, September 02, 2008

Hello, Hanna

Well, we did ask for rain to put water back into the swamp. Maybe we should be careful when we ask for such things at this time of the year. Today, the first order of business at the Audubon Center at Francis Beidler Forest was a discussion on Hurricane Hanna. The latest projected track shows the eye going right over Four Holes Swamp.

There is not too much that can be done at Beidler Forest beyond putting shutters on the windows and backing up important files to portable drives. The boardwalk will need to fend for itself...it's likely to lose all one-on-one battles with falling trees or branches dropping from 100 feet. Whether the winds howl at hurricane strength or not, this Friday's Audubon South Carolina board meeting may need to be postponed. The eye of Hanna is scheduled to arrive sometime in the early morning on Friday after the advance guard of wind and rain.

Hurricanes are not always a destructive force in the swamp. Obviously, in 1989, Hurricane Hugo rearranged the landscape, especially in the higher, drier areas that border the swamp. Over 80% of the pines and hardwoods were knocked down between the nature center and the swamp. Only 10% of the canopy was removed in the cypress-tupelo swamp itself, but much of the boardwalk was damaged by falling debris. However, ten years prior to Hugo, Hurricane David slowly worked its way up the coast with strikingly different results.

Hurricanes are fueled by warm water evaporating and condensing as it cools at higher altitudes. That condensed water falls as rain. Hurricane David hugged the coast, giving it a supply of warm water, and was slow-moving, so it had ample time to dump copious amounts of water across the landscape. Four Holes Swamp worked admirably as a wetland, filling with the tremendous volume of water and slowly releasing that water downstream into the Edisto River. Flooding occured where it should have occured (in the floodplain of the swamp) and was not considered disasterous because no human structures have been built in normally-wet areas of the swamp. What a novel idea!

Hurricanes help to move heat and water around the globe, which is beneficial overall. Tell that to the 10-year-old whose sleepover birthday party is Friday.

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