Tropical Storm Bill drenches Gulf Coast
Two possible tornadoes reported near New Orleans
(CNN) -- Tropical Storm Bill is soaking the already soggy Southeast with heavy rains, setting off flash flood warnings from Louisiana to Pensacola, Florida, late Monday night.
"I think we'll be talking about the rainfall even into Thursday," said National Hurricane Center Director Max Mayfield, who predicted that the storm would move through Louisiana, Mississippi, Alabama, eastern Tennessee, and eventually the Carolinas and Virginia.
He also warned that most people who die during a hurricane are killed by inland, freshwater flooding. "You don't want to let your guard down," he warned.
After coming ashore in Louisiana, the storm's maximum sustained winds dropped from 55 mph to 45 mph, but it also spawned several possible tornados as it moved across the New Orleans region and into neighboring Mississippi.
Mayfield said he expects Bill to fall to a tropical depression -- with sustained winds up to 38 mph -- by Tuesday morning.
At 11 p.m. EDT, the center of the storm was about 15 miles west of Bogalusa, Louisiana, and about 65 miles southwest of Hattiesburg, Mississippi. Bill is moving north-northeast at about 10 mph. It is expected to gradually turn to a northeasterly course, according to the NHC.
Tropical storm warnings were in effect from the mouth of the Mississippi River in Louisiana to Pascagoula, Mississippi.
Jim Ballow, assistant chief of operations for Louisiana's Homeland Security Office, said power outages in the southern coastal counties and isolated flooding in low-lying areas have been reported.
"We've also had some evacuations in those areas," he said.
Bill made landfall Monday afternoon in south-central Louisiana, and its winds sparked two possible tornados near New Orleans, officials said.
A tornado was reported 15 miles west of New Orleans in Reserve, according to meteorologist Glenn Buckland of the National Weather Service.
Chief Faron Duhe of the Garyville Volunteer Fire Department said Riverside Academy in Reserve suffered heavy damage to its gymnasium and one of its elementary buildings, and two mobile home parks sustained some damage. At least four people were injured, he said.
Another twister was reported by a fisherman in the marshlands of Plaquemines Parish, just southeast of New Orleans, Buckland said.
More than a dozen southern Louisiana parishes and three Mississippi counties -- Hancock, Harrison and Jackson -- are under a tornado watch, according to the weather service.
Louisiana Gov. Mike Foster declared a statewide state of emergency Monday afternoon as a "precautionary measure," so state resources could easily be made available if necessary, spokesman Steven Johnson said.
Gov. Ronnie Musgrove of Mississippi also declared a state of emergency for Harrison, Hancock and Jackson counties, spokesman John Sewell said. The Mississippi Emergency Management Agency has opened shelters in those counties.
Residents in low-lying areas of the three counties got a mandatory evacuation order about 5 p.m. EDT, according to state emergency management officials.
"It was a voluntary order, but then we started to have to get some people out using boats," said Mike Womack of the agency's Response and Recovery Bureau.
He reported moderate flooding in low-lying, rural areas.
Minor damage in coastal Louisiana
Earlier Monday, forecasters canceled a hurricane watch along the Louisiana coast.
Storm-driven waves crashed into vulnerable barrier islands, flooding main roads and side streets alike in water's edge towns like Grand Isle, about 50 miles south of New Orleans and nearly 100 miles east of the storm's landfall.
After landfall, Bill headed north across Atchafalaya Bay toward the swamps and marshes of St. Mary and Terrebonne parishes, and farther inland where the ground is still saturated from nearly a foot of rain that fell two weeks ago.
The National Hurricane Center warned of a "dangerous flood threat from rainfall and storm surge."
Bill is bringing as much as 10-15 inches of rain to some spots, CNN meteorologist Chad Meyers said, "and that's going to make some flooding" both along the coast and farther inland, where "much of the area is low-level farm land."
New Orleans closed 68 of the 120 floodgates around the city, said Lou Reese of the Orleans Parish Office of Emergency Preparedness, but so far there had been only localized flooding in the city's center.
"We have had some power outages due to high winds and tree limbs falling," Reese said, adding, "it could have been worse."
New Orleans Mayor C. Ray Nagin told local businesses to send employees home ahead of the storm, and nonessential employees at City Hall also left early, Reese said.
Bill Capo, a reporter for CNN affiliate WWL-TV in New Orleans, stood on the rain-drenched streets of Grand Isle and said water was breaking over the low-level levee that keeps the Gulf of Mexico out of the town.
Residents of Grand Isle hoped the worst of the storm would stay west of them, and Meyers said it likely would. As a precaution, the town's mayor issued a voluntary evacuation notice, Capo said.
The weather service said thunderstorms associated with the severe weather could sport wind gusts up to 70 mph along with torrential rains.
Bill formed in the Gulf of Mexico on Sunday, prompting warnings along the U.S. coast from Texas to Mississippi.
The first tropical storm of the year, Ana, formed in mid-April, nearly two months before the Atlantic hurricane season began June 1. It dissipated far out to sea without striking land.
Government forecasters predicted a busier-than-usual hurricane season this year, with 11-15 named storms and six-to-nine hurricanes. At least two are expected to be major hurricanes, with winds above 110 mph.