Huge and slow, Tropical Storm Isaac lumbered up through the Gulf of Mexico from Florida toward Louisiana and Mississippi on Monday night, growing stronger by the hour and putting coastal residents on notice of an extremely wet and potentially destructive next few days.
The tracking forecasts reached a consensus that the storm, which was a little over 200 miles southeast of the mouth of the Mississippi River and on the verge of becoming a hurricane, would land this afternoon somewhere around southeastern Louisiana as a Category 2 hurricane. But Isaac has been fickle and confounded predictions all along, and its intensification was just beginning.
The most serious danger may not be from the 100-mph winds but by the enormous amount of water the storm will bring with it and push in front of it. Officials encouraged those in low-lying areas to leave, warning of 12-foot storm surges along a broad swath of the coast and days of nonstop rainfall, in some places possibly adding up to 20 inches.
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“A slow-moving, large system poses a lot of problems,” Rick Knapp, the director of the National Hurricane Center, said in a conference call with reporters, describing the risks as “life-threatening, potentially.”
Louisiana residents wondering whether to stay or go were running out of time. Tropical-storm-force winds were expected to arrive overnight, rendering a last-minute escape more dangerous than sticking around. Gov. Bobby Jindal of Louisiana urged people in low-lying areas and places outside of levee protection to leave for safer ground, but in any case to make up their minds quickly.
A mandatory evacuation of the city of New Orleans is triggered by a Category 3 hurricane, a status Isaac is unlikely to reach. But the time frame for a safe and effective citywide evacuation expired on Monday anyway.
So those who remain here, as most have, will be marking the seventh anniversary of Hurricane Katrina on Wednesday not with ribbon cuttings and modest ceremonies as planned, but by hunkering down under heavy rains and winds.
Isaac promises a very different experience from Katrina. While it could possibly hit New Orleans directly — unlike Katrina, which landed in Mississippi but sent surge waters against the city’s faulty levees and flood walls — Isaac will have to contend with a $14.5 billion flood protection system that has been all but completed by the Army Corps of Engineers.
New Orleans Mayor Mitchell J. Landrieu said “there’s nothing this storm will bring us that we are not capable of handling.”
The storm forced the evacuation of workers from 346 oil and gas platforms in the Gulf of Mexico, responsible for 17 percent of domestic oil production and 6 percent of natural gas production, though it has so far had little effect on the price of commodities. Isaac has also led to at least one confirmed tornado, in Vero Beach, Fla., and put officials far beyond the shore on alert for more.
“We’re still recovering so we are geared up as much as any staff members can be,” said Yasamie August, information manager for the Alabama Emergency Management Agency, in a state that was devastated by tornadoes last year.
Mandatory evacuations have been announced in low-lying areas in Alabama and Mississippi, and shelters of last resort have opened all along the coast. The evacuations were also announced in several communities outside the levees in south Louisiana, as well as for the entire parish of St. Charles, west of New Orleans.
Renee Simpson, a spokeswoman for the parish, said the evacuation was called for because much of the parish is unprotected by levees from the surging gulf. She said a mandatory evacuation did not mean people would be arrested or roads closed, but amounted to a warning that, with electrical failures and extensive flooding likely, people who chose to say would essentially be on their own.
This did not seem to bother many St. Charles residents, who seemed mildly amused that people would leave for anything under a Category Three.
“Category 1 or 2, I’m staying; strong 3, 4 or 5, yeah, I’m out,” said Dale Daunie, a teacher in Luling. “We’re just going to grin and bear it for a little bit. You know, barbecue and make the best out of it.”
Louisiana officials warned that days of rain coming on top of dangerous storm surges would severely test local drainage systems and mean days without power.