By Charles East. Jr.

Louisianians know all about hurricanes. On the average, at least one of these raging storms hits the state every three years.

Like earthquakes in California, hurricanes in Louisiana are an impending natural threat, occurring only occasionally but bringing with them the potential for massive devastation.

The human lives lost and property destroyed justifiably dominate the headlines and news coverage in the wake of hurricanes. But another victim consistently takes a severe beating from the wind and water: Louisiana's environment.

There is no greater example of this than Hurricane Andrew, which struck Louisiana in August 1992. Incredibly, an estimated 184 million fish were killed in south Louisiana's bayous and inland waterways as a result of the hurricane.

"The average citizen can't even conceive of that many fish," says DEQ Secretary William Kucharski. "Andrew was an indication of just how fragile our environment is."

Brett Kriger, Deputy Assistant Director of Louisiana's Office of Emergency Preparedness, agrees. "Louisiana is, without a doubt, one of the most heavily populated, delicate environmental areas in the world," he says.

Dale Givens, Assistant Secretary for DEQ's Office of Water Resources, describes the Hurricane Andrew fish kill as an example of "how nature can do unto nature, causing massive environmental harm." As Andrew moved inland up the Atchafalaya River Basin, its powerful winds toppled trees and stripped off leaves and branches, clogging waterways with vegetation and debris, he explains. The resulting oxygen depletion caused the fish to suffocate.

Impacted were populations of largemouth bass, crappie, bream, freshwater drum, buffalofish, catfish, shad, striped mullet, carp, American eel, bowfin, paddlefish, and many others.

Hurricane Andrew was unusual, however, in having such a dramatic effect on freshwater species. Louisiana's coastal wetlands usually bear the brunt of environmental damage from hurricanes, but Andrew ravaged the coast and then churned inland up the Atchafalaya Basin, causing even further destruction.

In addition to fish, also at risk from hurricanes are oysters, shrimp, and crabs; waterfowl and migratory birds; and wildlife -- squirrels, rabbits, deer, nutria, and alligators, to name just a few.

Louisiana's Trinity Island is shown before (left - Click for a full size photo - 116K), and after (right - Click for a full size photo - 112K), Hurricane Andrew struck in August 1992.

Of these, oysters are generally the most vulnerable, according to Karen Feet, Assistant Administrator of the Marine Fisheries Division in the Louisiana Department of Wildlife and Fisheries (DWF). She notes that 25 percent of the state's public oyster seed grounds in the central coast area from the Mississippi River to the Atchafalaya Basin - were virtually wiped out by Hurricane Andrew.

Oyster culture in Louisiana is essentially a farming operation, with seed oysters from the state-managed seed grounds removed to private leases, where they are tended, cultivated, and fattened before being sold.

Despite Hurricane Andrew's devastating toll on fish and oysters, DWF officials say the direct loss of wildlife is usually minimal in a hurricane. "The biggest impact on wildlife is how much the habitat will be affected," says Dave Morrison, Program Manager for DWF's Wildlife Division. "Animals can survive and will return, but they may not if the habitat is destroyed."

	LOUISIANA: a history of hurricanes While Louisiana has experienced numerous hurricanes throughout its history -- including more than two dozen in this century -- several of them within the last 50 years stand out as particularly memorable. Here's a brief rundown of those storms, along with some of their unique characteristics: AUDREY June 27-30,1957 526 dead in Louisiana and Texas HILDA October 4-7, 1964 38 dead in Louisiana, Mississippi and Georgia BETSY September 7-10, 1965 74 dead in Florida, Mississippi and Louisiana CAMILE August 17-18, 1969 Category 5 (reported winds of 160 m.p.h. or more) 256 dead in Mississippi and southeast Louisiana $3.8 billion in damage JUAN October 26- November 6, 1985 3 landfalls in Louisiana; final landfall in Alabama 97 dead across the southeast United States ANDREW August 24-27, 1992 55 dead in Florida and Louisiana More than $25 billion in damage (the costliest U.S. natural disaster ever)

In fact, there are actually positive environmental aspects of hurricanes, according to wildlife and fisheries experts. When water is churned up by a hurricane, "it refurbishes the fisheries," says Bennie Fontenot, Administrator of the DWF Inland Fisheries Division. "Nutrients tied up in the water bottom can be stirred up and redistributed back into the aquatic system, and what is initially a disaster can have beneficial long-term effects."

Or, as DEQ's Dale Givens puts it, "Nature tends to heal itself."

That is particularly true when man takes a hand through stocking of new fish. Already, DWF reports, the largemouth bass population in the Atchafalaya Basin has fully recovered -- in terms of numbers of fish -- from damage caused by Hurricane Andrew in 1992.

However, the threat to Louisiana's coastline by hurricanes has no silver lining. In normal times, the state loses as much as 100 square kilometers of wetlands each year, an area the size of the District of Columbia. But hurricanes can escalate this process significantly.

"With a hurricane, 30 to 40 years' worth of slow dissipation can occur overnight," says Kriger.

Various published reports indicate that as much as 90 percent of shoreline erosion is directly attributable to hurricanes, mainly because of the low-profile nature of the barrier and chenier coasts. A chenier is a continuous ridge of material built upon a swampy deposit; it often supports trees, such as pines or evergreen oaks.

Johnnie Tarver, Administrator of DWF's Fur and Refuge Division, estimates that at least 100 feet of Louisiana's coastline is irretrievably lost during each hurricane. "Sand is pushed up on the existing marsh, and vegetation there dies," he explains.

Hurricanes are also the main causes of barrier island erosion. The low-lying barrier islands shelter Louisiana's broad expanse of coastal wetlands from the wave action of hurricanes and winter storms. Both the wetlands and their protecting islands have formed as a direct result of the shifting of the Mississippi River delta lobes during the past 7,000 years.

Meanwhile, successive hurricanes are tearing up sections of the Louisiana marshland. As these "mats" -- large masses of floating vegetation -- are ripped apart, the state's coastal area experiences further deterioration and loses habitat for birds and wildlife.

"Before" and "after" photos show the loss of sand on Louisiana's Raccoon Island caused by Hurricane Andrew in 1992. More than a mile of previously existing sandy beach (left - Click for a full size photo - 112K) was removed by the hurricane, leaving behind a patchy island formation (right - Click for a full size photo - 108K). The remaining island shown close up in the picture on the right is bordered in a red square in the picture on the left and is all that remains of the original island.

Environmental impacts of hurricanes, of course, are not limited to nature's effects on nature. One of the immediate environmental problems typically encountered in the aftermath of a hurricane is cleaning up hundreds and thousands of tons of debris. Household chemicals, refrigerants, motor oil, pesticides, and building materials are among the diverse pollutants that typically end up in waterways, groundwater, and, potentially, community and private water supplies.

"You could fill up a landfill with one storm's debris," says Kriger. "Without federal disaster assistance, cleaning up after a hurricane can bankrupt a community by filling up a landfill they were planning to use for 20 years."

Waves from Hurricane Elena pound Louisiana in 1985.

Hurricane cleanup approaches usually utilize a combination of some permitted burning, some landfill dumping, and some specially created hazardous materials sites, Kriger says.

Other potential environmental disasters caused by hurricanes include leaking oil rigs or platforms and chemical leaks. Kriger notes that 13 oil rigs were destroyed and 254 more damaged during Hurricane Andrew. Within the same time frame, seven barges broke loose on the Mississippi River in Baton Rouge, posing the threat of chemical leaks, according to Henrietta Alleman, Hurricane Program Manager for the Louisiana Office of Emergency Preparedness.

Given advance notice of an oncoming hurricane, petroleum companies can pump their oil from offshore facility ties to safer onshore tanks. They may then fill the vacated tanks with salt water to weight them down so they are not blown away or damaged during the storm.

Hurricane Andrew in 1992 caused this flooding at a Baton Rouge underpass.

Another possible impact triggered by a hurricane is a catastrophic loss of electric power, which can disrupt operations at chemical and industrial facilities, for example, causing discharges that pollute the environment.

Hurricanes, which Louisianians have become quite familiar with, are among the earth's deadliest and most destructive forces. Spawned in the tropics, these gigantic weather systems deliver high winds, flooding rains, huge waves, and storm-surge flooding to locations along the United States' Gulf of Mexico and Atlantic coasts.

Once winds associated with a tropical depression reach 39 miles per hour (m.p.h.), the system is "upgraded" to a tropical storm and is assigned a name. When wind speeds escalate to 74 m.p.h., the storm officially becomes a hurricane.

Hurricanes are classified by their relative strength into five categories. The lowest, Category 1, has winds ranging from 74 to 94 m.p.h. and a typical storm surge of four to five feet. The most severe storms, Category 5, carry maximum winds of more than 155 m.p.h., with storm surges of 18 feet or more above sea level.

Fortunately for the U.S. coast, "Cat 5" storms are relatively rare. Of all of Louisiana's hurricanes, only Camille in August 1969 attained Category 5 strength.

Atlantic Basin hurricanes - those impacting the Gulf and Atlantic seaboards -- can develop anytime during their "season" -- June 1 through November 30 but peak activity typically is centered near the first week of September.

Charles East, Jr. (504) 344-7612) is Editor of Louisiana Environmentalist.

Photographs by C.C. Lockwood and LSU/Center for Coastal, Energy, and Environmental Resources Special Programs.