In a briefing with governors and mayors affected by Hurricane Ida, President Joe Biden vowed full government support.

"We're there to help you get back on your feet," Biden said.

Louisiana Gov. John Bel Edwards said he estimated nearly 2 million are without power.

Biden said, "We're in close contact with local electric providers to see what they need. They are all private providers. We don't control that, but we're doing all we can to minimize the amount of time it is going to take to get power back up."

In the meeting, Edwards touted the success of the levee system, saying none of them were breached. But, he added, "Damage is still catastrophic."

Edwards said a U.S. Coast Guard helicopter crew rescued seven patients from a hospital in Lafourche Parish after its roof was ripped off by the powerful winds.

-ABC News' Sarah Kolinovsky

At least one death has been reported in New Orleans, Mayor LaToya Cantrell said. Details have not been released.

This brings Ida's death toll to at least two. A 60-year-old man in Ascension Parish died Sunday when a tree fell on a home, officials said.

At an emotional news conference Monday, Cantrell said the "worse-case scenario" with Ida "did not happen."

"We did not have another Katrina … we should all be grateful," she said.

Cantrell said New Orleans has a few collapsed buildings but not widespread destruction.

However, power is out throughout the city, 911 is not available and there are small pockets of standing water from blocked drains. The mayor stressed that residents should shelter in place.

-ABC News' Alexandra Faul

Ida, one of the strongest hurricanes to make landfall in Louisiana, has dropped 18 inches of rain on parts of the state.

New Orleans has been hit with 13.7 inches of rain.

Numerous flash flood warnings remain in effect across parts of Louisiana, Mississippi, Alabama and the Florida Panhandle.

Ida is expected to weaken to a tropical depression Monday before bringing heavy rain and possible flooding to the Tennessee Valley Monday night through Tuesday.

By Wednesday and Thursday the storm will hit the Mid-Atlantic and the Northeast. The forecast calls for 4 to 6 inches of rain and possible flash flooding.

-ABC News' Melissa Griffin

Ida significantly damaged Louisiana's Ochsner Health system, though neither patients nor employees have been injured, hospital officials said Monday.

About 65 patients at two of Ochsner Health's facilities have been evacuated, they said. Ochsner Health officials said they've also been asked to help evacuate about 100 patients from Terrebonne General Health System in Houma, Louisiana.

Terrebonne General Health System said it "suffered structural damages" and has no water from the parish. Terrebonne General said it's working to complete a "smooth transition of care" to other facilities."

-ABC News' Alexandra Faul

Louisiana Gov. John Bel Edwards provided another update on the damage from Hurricane Ida Monday evening.

Edwards said the state is still in a search and rescue mode as torrential rain and strong winds from the tropical depression continue to hit the state.

He said the entire southeastern section of the state is without power and over 1 million people are affected.

"There are an awful lot of unknowns right now," Edwards said. "I can't tell you when the power is going to be restored."

Edwards said the priority is to restore electricity to critical infrastructure and services, such as hospitals and dialysis centers.

Three hospitals were evacuated and a fourth is in the process of moving their patients, according to the governor.

Edwards said there was a "silver lining" from the storm in that there have been no reports of breached levees. There may have been a few levees where water overflowed, but the levees held up in critical locations, including New Orleans, according to the governor.

"They did not fail," he said.

Edwards urged homeowners who evacuated to not return to their homes until their parish leaders give the all-clear.

The Louisiana National Guard rescued 191 citizens and 27 pets so far across Jefferson, St. John the Baptist and Orleans parishes, Edwards said. They are conducting more sweeps through the affected areas.

The governor urged homeowners in affected areas to stay safe, as most hurricane fatalities take place long after the storm hits. He reminded people to use generators outside their houses, avoid driving through deep waters and not exert themselves during cleanups.

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Edwards did warn that he expects the death toll to rise, but said the numbers won't be as high if people heed warnings.

"This is a tough blow, but things are going to be OK," he said.