At least 48 people have died in the US northeast after Hurricane Ida's remnants caused record-breaking rainfall and mass flooding, according to multiple reports on Friday.

New Jersey continues to have the highest death toll with 25 fatalities recorded after roads became inundated with fast-moving floodwaters. A majority of those who died perished either in their cars after they became submerged, or after attempting to flee their vehicles in fast-moving waters, according to the Associated Press.

Further north in New York City, 13 people died, according to Mayor Bill de Blasio. Other deaths were recorded in Connecticut, Maryland, New York state and Pennsylvania.

Ida's overall death toll has hit 61, including deaths that occurred in three other states outside of the region.

State authorities from the Gulf coast to the northeast are continuing the cleanup effort after Ida made landfall on Sunday in Louisiana as a dauntingly powerful Category 4 hurricane, one of the strongest ever recorded in the continental US.

In New York City, authorities are continuing efforts to restore full train service as the Metropolitan Transportation Authority warned residents "service may not be frequent."

"Some lines have *extremely* limited service. In Queens, consider LIRR if possible," it said on Twitter, referring to the Long Island Rail Road, an alternative commuter rail system.

US President Joe Biden declared states of emergency in New York and New Jersey on Thursday, and is slated to travel to Louisiana on Friday to survey ongoing cleanup efforts and meet with local officials./agencies