Michael Palmer and Carin Schultz work to clear her car of snow and remove it from Union street on November 20, 2014 in the suburb of Hamburg, Buffalo, New York

Weather forecasters and emergency officials warned Sunday that melting snow would lead to heavy flooding in parts of the US northeast, with hundreds of thousands of people told to brace for fast-rising waters.

A flood watch was in effect until Wednesday in several counties in and around Buffalo in New York state after record-breaking snowfall killed at least 14 people, as Mother Nature struck its first blow of winter in the US, dumping more than six feet (two meters) of snow on Wednesday-Thursday.

Below-freezing temperatures had started to give way to warmer weather, a relief for some while posing a new threat for others, including the potential for roof collapses.

"While the snow has stopped, and we have made great progress on snow removal efforts, we are not out of the woods yet as the potential for flooding is great," said Erie County executive Mark Poloncarz.

"We are keeping an eye on area creeks, streams and low lying areas for flooding."

The New York state national guard was out in force to help residents dig out of their homes in hard-hit Erie and several other counties, while forecasters predicted the potential flooding from could be exacerbated by showers on Sunday and Monday.

"Large amounts of melt will produce considerable quantities of water, which may build quickly before receding," Poloncarz said.

New York Army National Guard soldiers use engineering equipment to assist in snow removal on November 20, 2014 efforts in Buffalo, New York

Authorities urged people to clear storm drains in front of their homes, and to get any valuables out of their basements.

Driving bans—enforced by the National Guard—and states of emergency were still in effect in several cities or towns, including Buffalo.

New York Air National Guard clear snow near Buffalo, New York, November 21, 2014

Many of those who died lost their lives while clearing mounds of from their cars and homes.

The respite from the cold looked set to be only brief, forecasters warned, with more chilly weather blowing in mid-week.