Wind-chill warnings extend from Estevan,  Sask., through Manitoba and Ontario, and east to Lac-Saint-Jean, Que., this morning, as Canada faces yet another bout of extreme cold.

In the U.S., a blast of freezing rain and snow was expected to hit even the Deep South, with tourist destinations such as Charleston, S.C., Savannah, Ga., Pensacola, Fla., and New Orleans expecting ice and snow.

Delta Air Lines officials say more than 1,800 flights have been cancelled ahead of a winter storm expected to pelt areas of the Southeast with sleet and snow.

"A snow squall watch is also in effect for eastern Lake Ontario, as a shift to southwest winds could punch a squall on shore later this morning with the potential for hazardous conditions later today along Highway 401 from Cobourg through Quinte to Kingston," CBC meteorologist Jay Scotland reported Tuesday morning.

Toronto is expected to avoid snow, but it will be windy with a high of –14 C, feeling much colder with the wind, Scotland said.

In Atlantic Canada, it's cold in the Maritimes but fairly quiet, although roads may be slick Tuesday morning after Monday's mild and wet weather followed by a cooldown.

Fredericton will reach a sunny –12 C and Halifax will top out at –8 C, with a few scattered flurries and variable cloud for Nova Scotia.

Rain moves east

For Newfoundland, a rainfall warning remained in effect for the southern Avalon Peninsula, with five millimetres of rain expected Tuesday morning.

The rain was expected to move east as the temperature continues to fall, down to about 0 C in the afternoon in St. John's and –9 C Tuesday night.

Deep Freeze Illinois

Bundled-up commuters exit a Metra commuter train at Chicago's Union Station Monday morning. (Rich Hein/Sun-Times/Associated Press)

In Western Canada, light rain fell overnight along the B.C. coast, with light snow (and possible patchy freezing rain) through the northern/central interior, Scotland said.

Vancouver will see more showers Tuesday, with steadier rain working in at night and a high of 8 C in the afternoon.

The Prairies are clear today, and much of southern and central Alberta will enjoy mild temperatures.

Chinook winds will roar out of the Rockies (gusty through the passes), and Edmonton and Calgary will see highs of 0 C and 6 C respectively, Scotland said.

Winnipeg at –21 C

The eastern Prairies remain cold, with wind-chill warnings for southern Saskatchewan and southern Manitoba. Saskatoon and Regina will reach –14 C and –15 C, respectively.

Winnipeg will be bone-chilling, with a high temperature of –21 C.

In the U.S., forecasters were predicting snow and ice from Texas to the Carolinas by mid-week as precipitation moving in from the south met with cold air already chilling the region.

In the Carolinas, many school districts were running on half-day schedules on Tuesday, so students could head home before the worst of the storm system hit. In North Carolina's Outer Banks, barrier islands that are popular with tourists during the warm seasons, residents were bracing for as much as 20 centimetres of snow.

Snow is also expected in South Carolina, where the state's Department of Transportation planned to send crews out Tuesday to treat roads with sand and brine to ease any troubles caused by ice.

'Dangerous situation'

Elsewhere, some schools and government offices already closed in Mississippi ahead of the rare snow event.

"This is a very dangerous situation because snow and ice are very rare for extreme southern Mississippi," Robert Latham, executive director of the Mississippi Emergency Management Agency, said in a release. "We need everyone to have an emergency plan together for this."

In Louisiana, state Public Service Commission chairman Eric Skrmetta told residents to be prepared by stocking up with food, fuelling cars and having cash on hand, calling the icy forecast for the next couple of days "decidedly grim."

Donna Vidrine, a cashier at Simcoe Food World in Lafayette, said her store began getting busy Monday.

"They're buying things like canned goods — nonperishable items — and bottles of water and diapers for their baby," she said.

With files from The Associated Press