Flash flooding killed at least 44 people in four Northeastern states as remnants of Hurricane Ida unleashed torrential rains that swept away cars, submerged New York City subway lines and grounded airline flights, officials said on Thursday.

Across large swaths of New York, New Jersey, Pennsylvania and Connecticut, residents spent the day coping with water-logged basements, power outages, damaged roofs and calls for help from friends and family members stranded by flooding.

At least 13 people lost their lives in New York City, along with three in suburban Westchester County. New Jersey Governor Phil Murphy said in a tweet at least 23 people from that state had perished in the storm.

Among the fatalities, three people were found dead in a basement in the New York City borough of Queens, while four residents of Elizabeth, New Jersey, died at a public housing complex flooded by 8 feet (2.4 m) of water.

U.S. President Joe Biden declared that an emergency exists in the states of New Jersey and New York and ordered federal assistance to supplement local response efforts due to conditions resulting from the remnants of Hurricane Ida, the White House said late on Thursday.

Roadways were transformed into river-like torrents in minutes as the downpours struck on Wednesday night, trapping drivers in quickly rising floodwaters. Scores of vehicles were found abandoned on area roadways Thursday. In Somerset County, New Jersey, at least four motorists were killed, officials said.

A victim in Maplewood Township, New Jersey, was swept away while he was apparently trying to remove debris from storm drains in the area, police said.

"Sadly, more than a few folks have passed as a result of this," Murphy said at a briefing in Mullica Hill in the southern part of the state, where a tornado ripped apart several homes.

The National Weather Service confirmed two tree-snapping tornadoes also struck Maryland on Wednesday, one in Annapolis and another Baltimore. A 19-year-old was reported to have died after trying to rescue his mother from a flooded apartment in Rockville, Maryland, according to the Washington Post.

The damage came three days after Ida, one of the most powerful hurricanes ever to strike the U.S. Gulf Coast, made landfall on Sunday in Louisiana, destroying entire communities.

But the loss of life in the Northeast dwarfed the confirmed storm-related death toll of nine in Louisiana.

In Conshohocken, Pennsylvania, outside Philadelphia, the Schuylkill River inundated hotels, warehouses and condominiums that line the river. Emergency squads were waiting for the waters to recede on Thursday before starting evacuations of possibly hundreds of people who live in nearby apartments, officials said.

Four people died in suburban Philadelphia as a result of the storm, according to county spokesperson Kelly Cofrancisco. A Connecticut state trooper perished after his cruiser was swept away in floodwaters in the town of Woodbury early Thursday, state police said.

Video footage on the Weather Channel showed flames billowing from a house in the riverfront town of Manville, New Jersey, where flooding prevented access by fire trucks. The house next door appeared to have burned down to the waterline on a street where parked cars were submerged.