Speaking to Reuters, Erie County Deputy Executive Richard Tobe warned that "there are buildings that are in danger."
The storm had already dumped more snow than many places see in a full season — even in wintry western New York. Some homes had the equivalent weight of two or three pickup trucks bearing down on their roofs.
More from NBC News:
Dramatic Aerial Photos Show Force of Buffalo Storm
Jets-BillsGame Moved From Snowy Buffalo to Detroit
Where's the snow? Not in Alaska's largest city
"It's getting heavier," Cheektowaga resident Thomas Mudd Jr. told The Associated Press as he spent several hours with his wife shoveling 4 to 5 feet off their roof. "It's supposed to warm up and we're supposed to get rain on the weekend, which will make it even heavier. So I didn't want my roof collapsing."
Because the Buffalo area is so snowy, building codes require homes and businesses to be able to handle up to 50 pounds per square foot on their roofs, which would be about as heavy as a slab of concrete 4 inches thick, structural engineer Mark Bajorek told The Associated Press.
Little or no snow was expected in the area on Friday, and the forecast called for a chance of rain on Saturday and more on Monday along with temperatures approaching 60 degrees.
Read MoreScenes from the snow: Be glad you're not in Buffalo
NBC News meteorologist Bill Karins warned that "rapid snowmelt and localized flooding" was likely in parts of western New York into early next week.
Meanwhile, authorities said Thursday that a 60-year-old man with a history of heart problems had a fatal heart attack while retrieving his snowblower in Cheektowaga and that two other people died outside their homes from apparent exposure to the cold, one in the Erie County town of Boston and the other in Niagara County. The early winter blast had been linked to a total of 10 deaths by early Friday.
States of emergency were in effect for 10 counties.
The storm dumped an estimated 220,000 tons of snow on Ralph Wilson Stadium outside Buffalo, piling it halfway to the crossbar in each end zone and forcing the National Football League to move Sunday's game between the Buffalo Bills and the New York Jets. The league said Thursday that a new location hadn't yet been determined.
"If you ask me today, right now, my two cents would be it's impractical to do the game because it could jeopardize public safety," Cuomo told reporters. Erie County Executive Mark Poloncarz said he couldn't guarantee that the usual complement of law enforcement officers and emergency vehicles would be available for the game.
Read MoreWhat happens when it all melts? Floods likely
The Bills had offered $10 an hour and free tickets to the game to anyone who volunteered to shovel out the stadium.
—The Associated Press and Reuters contributed to this report.