New Orleans Mayor LaToya Cantrell on Tuesday declared a night-time curfew after Hurricane Ida left Louisiana and neighbouring states without power.
Ms Cantrell called it an effort to prevent crime as the entire city is out of electricity.
She expects the main power company Entergy will be able to provide some electricity to the city by Wednesday evening, but stressed that does not mean a quick, citywide restoration. Rather, she said, the energy company will be able to begin restoring its mangled distribution system of snapped poles and tangled lines.
She said residents would see progress, but also acknowledged frustration in the days ahead.
“We know it’s hot. We know we do not have any power and that continues to be a priority,” she told a news conference.
There was a glimmer of hope early Wednesday when Entergy announced its crews had turned “power on for some customers in Eastern New Orleans.” Still, power and water outages affected hundreds of thousands of people, many of them with no way to get immediate relief.
A company statement said reconnecting all of New Orleans “will still take time given the significant damage” to the city’s power grid.
Ida, one of the most powerful hurricanes ever to hit the US Gulf Coast, had weakened to a tropical depression by late Monday as it churned over Mississippi and Tennessee on Tuesday.
The storm, which slammed Louisiana with rain and killed at least two people, caused widespread power outages across Louisiana, Mississippi and Alabama, and prompted rescue operations in flooded communities around New Orleans.
By early Tuesday, more than one million customers remained without power in Louisiana, the PowerOutage website showed.
Residents in the hardest-hit areas could experience power outages for weeks, utility company Entergy said on Monday. Many water systems in the state were also out.
Officials in Jefferson Parish in the New Orleans metropolitan area asked residents to conserve water to prevent sewage system backups.
Adding to the misery was the steamy weather. A heat advisory was issued for New Orleans and the rest of the region, with forecasters saying the combination of high temperatures and humidity could make it feel like 41°C on Tuesday and 42°C on Wednesday.
City officials announced seven places around New Orleans people could receive a meal and sit in air conditioning. The city is also using 70 transit buses as cooling sites and will have drive-through food, water and ice distribution locations set up on Wednesday, Ms Cantrell said.
Bonnaroo Music & Arts Festival in Tennessee moved to cancel its three-day festival scheduled to start on Thursday following the storm as organisers say the waterlogged festival grounds are unsafe for driving or camping.
Organisers added that tremendous rainfall over the past 24 hours — remnants of Ida’s powerful winds and rain — has saturated the paths and camping areas.
The festival had earlier warned fans that camping capacity would be reduced because of the rain, but by Tuesday afternoon, the festival said its central stage area was also waterlogged.
Two people were killed and 10 injured in a road collapse on a Mississippi motorway that probably was triggered by heavy rains unleashed by Hurricane Ida, officials said on Tuesday.
Three people among those injured were in critical condition, the Mississippi Highway Patrol reported. The collapse affected a portion of Highway 26 in George County, about 85 kilometres north-east of Biloxi.
“We've had a lot of rain with Ida, torrential,” Mississippi Highway Patrol officer Calvin Robertson said. “Part of the motorway just washed out.”
Seven vehicles plunged into a 15-metre ditch that resulted from the motorway collapse, local media reported.
Widespread flooding and power cuts also slowed efforts on Tuesday by energy firms to assess damages at oil production facilities, ports and refineries.
Climate change is fuelling deadly and disastrous weather across the globe, including stronger and more damaging hurricanes.
Ida made landfall on Sunday as a Category 4 hurricane, 16 years to the day after Hurricane Katrina, evoking memories of a disaster that killed more than 1,800 people in 2005 and devastated New Orleans.
But a $14.5 billion system of levees, flood gates and pumps designed after Katrina's devastation largely worked as designed during Ida, officials said, sparing New Orleans from the catastrophic flooding of 2005.
While search-and-rescue missions are focusing on those who sheltered in place, AFP reported that local officials urged people not to return to the area as there was a lack of services and trees, debris and downed power lines continue to pose a hazard.
“I know people are anxious to get back home, but I am urging you to wait until you get the all clear from your local officials. The storm may have passed but dangers still remain,” Louisiana Governor John Bel Edwards said at televised a press conference.
The state's healthcare systems also appeared to have largely escaped catastrophic damage at a time when Louisiana is reeling from a resurgence of Covid-19 infections that has strained hospitals.