As biting cold temperatures sweep across a large swath of the US, parts of the Great Lakes face up to two feet of additional lake-effect snow through Tuesday – the latest complication for cities already blanketed by snowfall amid post-Thanksgiving travel.

A LAKE EFFECT SNOW WARNING continues for Ashtabula, Cuyahoga, Geauga, and Lake Co. until 7 a.m. Tuesday. Another 6 to 18″ of snow will be possible through Tuesday morning locally.

Areas of Michigan, northern New York, Ohio and Pennsylvania could receive several feet of snow over the weekend. The storm already brought deep snow to portions of Michigan’s Upper Peninsula.

In late fall and winter, lake-effect snow is a common occurrence in the Great Lakes region. "Lake-effect snow occurs when cold air, often originating from Canada, moves across the open waters of the Great Lakes.

Lake-effect snow blowing in from the Great Lakes has blanketed parts of Michigan, Ohio, Pennsylvania and New York, stranding hundreds of vehicles on roads and snarling post-Thanksgiving travel plans for millions.

More than 4 million people across five states were under winter storm alerts on Sunday as heavy lake-effect snow continued to bury the Great Lakes region, prompting emergency declarations and the deployment of National Guard troops to rescue stranded motorists.

Nearly two million people remain under lake-effect snow warnings through early Monday. CNN’s Polo Sandoval reports.