New Orleans: Torrential rain dumped by Hurricane Isaac threatened
to burst a dam in Mississippi on Thursday, triggering the mass
evacuation of local residents, while large areas of the region were
still flooded and without power but getting ready to mop up.Isaac, which was downgraded to a tropical depression on Thursday, did little damage to New Orleans, where stronger barriers were installed after Hurricane Katrina in 2005. Only one fatality linked to the storm has been confirmed so far.
But it produced a soggy mess across widespread areas of the US Gulf Coast and could still bring heavy downpours and 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 about 1 million overnight. As winds subsided, crews were able to start assessing damage.
While New Orleans and the coast got started with clean-up, new worries developed about a potential failure of Lake Tangipahoa Dam in Mississippi's Percy Quin State Park.
Authorities ordered the immediate evacuation of tens of thousands of residents in nearby communities in Louisiana and Mississippi as a protective measure.
The earthen dam, in Pike County, is about 100 miles (160 kilometers) north of New Orleans. It was damaged, but not breached, Wednesday night's tumultuous downpours.
Heavy equipment and pumps were brought in to start a controlled water release to the Tangipahoa River, relieving pressure on the dam.
"Every precaution is being taken to protect the safety of the people and property," said Mississippi Governor Phil Bryant.
Ken Graham, forecaster with the National Weather Service in New Orleans, said the Tangipahoa River near Kentwood - hometown of pop singer Britney Spears - is already 14 feet (4.3 metres) above flood stage and is expected to rise to 16 feet (4.9 meters) by Friday morning.
"That takes it to a pretty big flood event, and that's just from the rain," he said.
Additional heavy rain is not expected as the remnants of Isaac move away, but the National Weather Service said the dam "may potentially fail" and is keeping a flash flood watch in effect for Pike Country through 5 p.m. ET (2100 GMT) on Friday.
State officials were at odds about the risks posed by the dam. Louisiana Governor Bobby Jindal warned of potential "record flooding" downstream, while officials in Mississippi downplayed the possibility of a dangerous water release.
"Even if that dam would have a catastrophic break, the flood plain in Pike County would be able to handle it, so it would not significantly affect the river," said Greg Flynn, spokesman from the Mississippi Emergency Management Agency. "They don't expect any wall of water to go down the river."
Damage assessments
In areas struck earlier by Isaac, the process of checking for damage and restoring halted operations began.
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 has 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. Benchmark Brent crude was little changed in Thursday afternoon trading at about $112.75 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 US Army Corps of Engineers. "The levees worked," Jindal said.
Among the items spared in the storm were thousands of bags of green coffee stored in New Orleans warehouses that had sustained damage during Katrina.
"No major damage to the buildings and no damage to stored product," Allan Colley, president of Dupay Storage and Forwarding, said in an email.
Dusk-to-dawn curfews, designed 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 humour 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 neighbours. That's what New Orleans is known for.
Surrounding parishes hit
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 m) of water. Dozens of residents who had attempted to ride out the storm had to be plucked from their rooftops.
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.
National Guard troops and police moved into the town Thursday afternoon as some local residents navigated flooded streets in boats. Overall, troops have rescued or evacuated more than 3,000 Louisiana residents and three tractor-trailer loads of pets, Jindal said.
Drought relief
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.
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.
But US President Barack Obama still declared the impact on Louisiana and Mississippi major disasters and ordered federal aid to supplement state and local recovery efforts.
© Thomson Reuters 2012
