NEW ORLEANS (Reuters) - The remnants of Hurricane Isaac trudged north on Thursday and U.S. Gulf Coast residents started to mop up and assess damage, even as much of Louisiana was still flooded and without power.
Isaac, which was downgraded to a tropical depression on Thursday after hitting the region as a Category 1 hurricane, did little damage to New Orleans, where stronger barriers were installed after 2005’s Hurricane Katrina almost laid waste to the city.
Some key regional infrastructure, including ports, airports and oil refineries, was expected to be operating again on Friday.
Still, Isaac left a soggy mess across widespread areas of the U.S. Gulf Coast and could still bring heavy downpours and lowland flooding before moving into the central United States - where rain is badly needed - over the next few days.
Some 700,000 homes and businesses in Louisiana and Mississippi were still without power on Thursday, down from a peak of about 1 million. As winds subsided, crews were able to start assessing damage to power lines.
Authorities on Thursday, mindful of the lessons of Katrina, paid close attention to damage done to the earthen Lake Tangipahoa Dam in Mississippi’s Percy Quin State Park, about 100 miles (160 km) north of New Orleans, by days of relentless rainfall.
Officials asked tens of thousands of residents from nearby rural communities in Louisiana and Mississippi to evacuate as a precaution after warnings that the dam might break.
By day’s end a plan had been hatched to avert the danger. A controlled breach is planned for Friday, and the lake that is held back by the dam is expected to be drained as well.
“There will not be a wall of water moving toward Tangipahoa Parish,” said Mississippi Governor Phil Bryant.
In areas struck earlier by Isaac, the process of checking for damage and restoring halted operations began in earnest.
Isaac never came close to the power of Katrina, which was a Category 3 hurricane on the five-step Saffir-Simpson scale when it smashed into New Orleans on August 29, 2005.
Still, U.S. President Barack Obama still declared the impact on Louisiana and Mississippi major disasters and ordered federal aid to supplement state and local recovery efforts.
The storm caused anywhere from $500 million to $2 billion in insured onshore losses, according to estimates by two firms that project damage for the insurance industry.
The oil and gas industry in the Gulf of Mexico has so far reported no major storm-related damage to infrastructure although one Louisiana refinery had flooding.
Energy production was expected to start ramping up again, after nearly grinding to a halt as Isaac closed in on Louisiana on Tuesday. U.S. crude oil fell as companies found little damage from the storm, closing at $94.62 a barrel.
Multibillion-dollar defenses built to protect New Orleans itself, after it was ravaged by Katrina almost exactly seven years ago, passed their first major test, according to the U.S. Army Corps of Engineers.
The Port of New Orleans was scheduled to reopen on the Mississippi River on Friday. Staff reported no flooding and only minimal wind damage to industrial and cargo facilities.
With energy restored, Louis Armstrong New Orleans International Airport is also expected to be open on Friday.
Dusk-to-dawn curfews, imposed to help prevent any repeat of the looting that occurred in New Orleans in the days after Katrina struck in 2005, were lifted on Thursday.
Only about a dozen looting-related arrests were reported in the city by Thursday morning but the streets were unusually quiet, still littered with downed branches, fallen trees and pieces of roofing material.
In the historic French Quarter, a few people were out taking down the boards they had nailed up over store windows. Officials urged patience and good humor during the clean-up.
“Our tempers tend to flare,” said New Orleans Councilwoman Cynthia Hedge Morrell at the news conference. “My advice would be sit on the front porch and talk to your neighbors. That’s what New Orleans is known for.”
But massive rains and storm surge from the Gulf inundated low-lying communities outside the federal flood containment system protecting New Orleans, forcing the evacuation of thousands of people from their homes and some dramatic rooftop rescue operations.
Hardest hit was Plaquemines Parish, southeast of New Orleans, where floodwaters overtopped at least one levee on Wednesday and left many homes under about 12 feet (3.6 meters) of water. Dozens of residents who had attempted to ride out the storm had to be plucked from their rooftops.
Late on Thursday, local officials confirmed the death of a man and a woman in Braithwaite, the hard-hit town in Plaquemines County. The pair apparently drowned in their kitchen, bringing known deaths from Isaac to three.
In Slidell, a town of about 27,000 people northeast of New Orleans, the surge from Lake Pontchartrain left the Eden Isle community under about a foot (30 cm) of water.
“You’d have never made me believe a Category 1 would dump this much water,” said Sam Caruso, 71, a former mayor of the town who was touring it in his pickup truck.
As the focus on Isaac shifted from the coast, many in its projected path further north have been praying it will bring rain desperately needed to ease a drought. Summer crops are in tatters and many rivers and dams are critically low.
Storm watchers have turned to Tropical Storm Leslie, currently 1,060 miles (1,705 km) east of the Windward Islands with wind speeds picking up. Leslie could become a hurricane as soon as Friday but is not seen as a threat to land.
Additional reporting by Ben Gruber and Kathy Finn in New Orleans; Emily Le Coz in Tupelo, Missisippi; Chris Baltimore in Houston; David Adams and Kevin Gray in Miami; Writing by Tom Brown, Anna Driver and Ros Krasny; Editing by Jackie Frank, Eric Walsh and Lisa Shumaker