Snowfall of up to two metres in western New York state is prompting local officials to further restrict road travel, and forced airlines to cancel flights across the Buffalo area just ahead of the busy Thanksgiving holiday week.
New York Governor Kathy Hochul called in the National Guard, deploying about 70 members to help with snow removal in the hardest-hit parts of Erie County.
Erie County, which has felt the brunt of the snowfall, recorded totals of 1.95 metres in Orchard Park, the site of the NFL's Buffalo Bills home field.
Squalls began blowing in from Lake Erie and Lake Ontario on Thursday to produce the region's first major snowstorm of the season, more than a month before the start of winter.
According to the National Weather Service, conditions could persist through Monday morning.
Nearly a metre of snow had fallen at Buffalo Niagara International Airport, where many flights were cancelled on Saturday.
Buffalo, the second-largest city in New York, was placed back under a travel ban on Saturday morning.
"This has been a very unpredictable storm with the snow bands moving, back and forth, north to south," Buffalo Mayor Byron Brown told CNN. "The snow has come down very fast, very wet, very heavy."
Buffalo saw daily record snowfall of more than 40cm, topping the one-day record of 19.3cm recorded in 2014, the National Weather Service said on Saturday.
At least two deaths were reported on Friday.
Erie County Executive Mark Poloncarz said in a tweet that two residents died of apparent heart attacks while shovelling snow.
County officials warned people to stay off roads to keep clear for snow removal crews.
Illustrating the highly localised nature of lake-effect snow, accumulation levels varied widely across the region.
Still, 11 counties remained under an emergency declaration issued on Thursday by Hochul.
After a northward shift that will impact the Niagara County, the Buffalo area should brace for more snowfall late on Saturday, according to Erie County Department of Homeland Security and Emergency Services Commissioner Daniel Neaverth.