Biting cold temperatures – below-freezing in some areas – will sweep across a large swath of the United States Sunday while record-breaking, lake-effect snow makes post-holiday travel treacherous and nearly “impossible” in parts of the Great Lakes region.

People in parts of New York, Pennsylvania and Ohio faced low temperatures and several feet of snow over the weekend.

Near Lake Erie in Conneaut, Ohio, where additional snow accumulation could reach up to 5 inches on Sunday, a home’s roof appeared to be draped in snow Saturday, video shared with CNN by resident Ashley Drew shows. The home’s blue front door was only partially visible behind a wall of snow, as snow continued to fall.

Nearly 70% of the continental US will feel the chill of temperatures below 32 degrees over the next few days. Some areas including New York City, Chicago, Atlanta, Minneapolis and Cincinnati will experience below-average temperatures for the entire week.

Four million people are currently under lake-effect snow warnings, set to expire Sunday night through Monday.

In Amherst, New York, located in Erie County, below-freezing temperatures prompted authorities on Saturday to issue a code blue alert, inviting anyone in need of shelter during the extreme cold to call for help.

Erie County is among 11 counties under a state of emergency that New York Gov. Kathy Hochul issued Friday in response to the ongoing lake-effect snowfall that began late Thursday.

The declaration impacts western and central New York, containing the Buffalo area and many areas near Lakes Erie and Ontario.

“My administration is working around the clock to respond to the snowstorm in Western New York and the North Country,” Hochul said on X Saturday. “Our state agencies and over 100 National Guard members are on the ground to support storm operations.”

Pennsylvania Gov. Josh Shapiro also called in his state’s National Guard Saturday to assist any stranded motorists and ensure emergency responders can reach anyone trapped, he announced on X.

The outbreak of Arctic chill diving southward out of Canada will cause temperatures in much of the eastern half of the US to fall as much as 15 degrees to 25 degrees below average through the middle of next week, forecasters say.

“High temperatures (are) expected to be 10 to 20 degrees below average Sunday and Monday from the Northern Plains into the Ohio Valley, with the 10 to 20 degree below average temperatures spreading farther southeast along much of the east coast by Monday,” according to the National Weather Service’s Weather Prediction Center.

Lake-effect snow to dump several more inches

The wind-driven cold air flowing across the record warm water in the Great Lakes is responsible for the lake-effect snow that has already unloaded up to dozens of inches of snow in some locations, according to forecasters.

Through Monday, an additional 1 to 2 feet of snow could fall in parts of Pennsylvania, northern Ohio and western New York. Watertown, New York, could receive an additional 1 to 2 feet of snow, according to CNN meteorologists.

“The heaviest snow totals are expected downwind of lakes Erie and Ontario, affecting areas from northeast Ohio, far northwest Pennsylvania, western New York State and portions of northwest New York state,” according to the Weather Prediction Center.

North East, Pennsylvania, a borough in Erie County, recorded just over 42 inches of snow between Thursday night and Saturday afternoon while Erie, Pennsylvania, received 31 inches. Barnes Corners, New York, saw 45 inches of snow by Saturday afternoon, according to the weather service.

Nearly two million people remain under lake-effect snow warnings through early Monday.

Video showed several homeowners in Erie, Pennsylvania, hand shoveling large piles of snow and using snow blowers to clear the mounds from their driveways and walkways as snow continued to fall Saturday, according to CNN affiliate WICU.

Other video from storm chasers showed mounds of cars buried beneath snow in Erie County, Pennsylvania.

Kathy Davis, a resident of Tug Hill in northern New York, described Saturday’s heavy snow as a “good old-fashioned winter” in a video clip she shared with CNN affiliate WWNY.

“This is what I remember as a kid,” Davis said, according to WWNY. “It just keeps coming and coming.”

Forecasters warn of ‘very difficult’ travel, whiteout conditions

Matt Eisert, 58, of Columbus, Ohio, said he was visiting his father in Erie, Pennsylvania, during Thanksgiving when his parents’ home became surrounded by heavy snow.

“We grew up here, so we were always used to lake-effect snow when the warm unfrozen lake evaporates over cold winds blowing over it,” Eisert said.

The realtor said he still plans to return to Columbus sometime Sunday on a journey he expects to extend beyond three hours.

“I have blankets in the car, water, some protein bars. I always stock up and have a little road survival kit in my car,” Eisert said.

Several highway traffic cameras showed snowy conditions over highway in Ohio, Pennsylvania and New York Saturday,

The Ohio Department of Transportation in Akron said 25 crew members worked around the clock in Ashtabula County as lake-effect snow continued to fall in the county, where commissioners issued a state of emergency on Saturday, the county’s board posted via Facebook.

Post-holiday travel will continue to be “very difficult to impossible” for some motorists, with forecasters urging people to stay off the roads as whiteout conditions make driving “treacherous and potentially dangerous,” according to the National Weather Service office in Buffalo, New York.

“Delay all travel. If you must travel, drive with extreme caution,” the weather service warned Saturday. Buffalo’s lake-effect snow warning continues through Monday night.

Meanwhile, the Buffalo Bills showed the snow covering the field of its open-air Highmark Stadium in Orchard Park, New York, in a post on X Saturday. The team is scheduled to play the San Francisco 49ers on Sunday night.

The Bills on Friday began requesting help from fans to clear the field of snow ahead of game time. Erie County officials in New York said Friday they do not anticipate the snowy conditions will impact the game.

Lake-effect snow is likely to fall through 4 p.m. ET Sunday over Orchard Park, according to the New York State Weather Risk Communication Center.

CNN’s Gene Norman, Allison Chinchar, Artemis Moshtaghian, Taylor Galgano and Sam Joseph contributed to this report.