Hurricane Ida devastated southern Louisiana, leaving more than a million homes and businesses without electricity.

Authorities say flooding in four states in the Northeastern United States has killed at least 44 people, with cars and subway lanes sinking and planes canceled in New York City as Hurricane Ida receded.

Residents of large areas of New York, New Jersey, Pennsylvania and Connecticut spent their day helping flood-affected foundations, darkened, damaged roofs and flood-affected friends and relatives.

At least 13 people were killed in New York City and three in Westchester County. New Jersey Governor Bill Murphy said in a tweet that at least 23 people have died in the state due to the storm.

The White House declared a state of emergency in New York and New Jersey late Thursday, and ordered federal assistance to support the withdrawal of Hurricane Ida and local efforts to respond to the disaster caused by the weather.

The losses came three days after Hurricane Ida, the most powerful hurricane to hit the U.S. Gulf Coast, hit Louisiana on Sunday, devastating entire territory. But the death toll in the Northeast is higher than in Louisiana, where nine people died from the hurricane.

Governors of New York and New Jersey have asked residents to stay home while maintenance crews work to reopen roads and reopen subways and railroads.