HURRICANE Georges has not only left behind a trail of misery, it may also
force cartographers to redraw maps of the Mississippi Delta.
Until Georges roared through on 27 September, the Louisiana coast was
protected by a low-lying 50-kilometre arc of sand called Chandeleur Island. But
when Thomas Michot of the US Geological Survey in Lafayette flew over the area
after the storm, he saw 鈥渁bout a hundred鈥� islands, some separated by several
kilometres of water.
If Chandeleur Island has been permanently breached, this may have lasting
consequences for the region鈥檚 ecology. The shallow waters surrounding Chandeleur
contain one of the largest seagrass beds in the Gulf of Mexico, which supports a
wealth of invertebrates. These are in turn eaten by fish and birds.
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Louisiana鈥檚 coastal defences may also suffer. The island breaks the force of
storm waves before they reach threatened marshes along the Louisiana coast. It
also protects New Orleans, which is vulnerable to flooding despite being 60
kilometres inland.
The damage is the worst since photographic surveys began in the 1930s, says
Greg Stone of Louisiana State University in Baton Rouge. Although Georges was
not as severe as Hurricane Camille in 1969, it moved much more slowly, so the
island took more of a battering from waves and wind.
Geomorphologists consider Chandeleur one of America鈥檚 most threatened coastal
barrier islands and expected it to disappear within a few hundred years. The
damage wrought by Georges will hasten its demise.
