From Winnipeg to eastern Quebec, large swaths of Canada were under an extreme cold warning on Saturday as temperatures dropped deep into the negatives.

Environment Canada issued extreme cold warnings for the southern half of Manitoba, almost the entire province of Ontario, parts of Quebec, and parts of New Brunswick on Saturday. The agency also issued warnings for extreme cold and winter storms in areas of Newfoundland and Labrador.

In total, the agency issued warnings for 140 regions of Canada, Environment Canada senior climatologist Dave Phillips told CTV's News Channel on Saturday morning.

"These are wind chills that could be down to, certainly, -45 C or -50 C," Phillips said. "That could freeze flesh in a matter of minutes."

According to the agency, an Arctic ridge of pressure pushed temperatures in Winnipeg to a frigid -30 C overnight. With wind chill, those temperatures could feel more like -40 C or colder.

"We're really two different countries today," Phillips said. "I mean, my gosh, Toronto was 14 degrees colder than Yellowknife."

Meanwhile, in the City of Ottawa, "the coldest air of the season" is expected to cause temperatures to feel as cold as -45 C with wind chill and Torontonians faced temperatures that felt as cold as -40 C with wind chill on Saturday morning.

Even more extreme temperatures are forecast for parts of Quebec on Saturday, with Environment Canada calling for temperatures that feel as low as -38 C to -46 C with wind chill in Montreal and Quebec City.

Environment Canada issues extreme cold warnings when temperatures or wind chill create an elevated health risk.

While under extreme cold warnings, the agency urges residents to wear appropriate clothing, dress in layers with a wind resistant outer layer, wear warm socks, gloves, a hat and scarf, and change into dry clothing as soon as possible if they become wet.

The agency also notes that some residents are at greater risk than others for frost bite and hypothermia. These at-risk groups include:

• homeless people

• outdoor workers

• people living in homes that are poorly insulated (with no heat or no power)

• people with certain medical conditions such as diabetes, peripheral neuropathy and diseases affecting the blood vessels, people taking certain medications including beta-blockers

• winter sport enthusiasts

• people who consume excess alcohol

• infants and seniors

"It is quite a dangerous kind of situation," Phillips said. "For homeless people it makes a difficult life even more difficult."

Deep freeze comes amid relatively mild winter in Eastern Canada

While the agency said temperatures are expected to improve "marginally" on Saturday afternoon, they were expected to drop again overnight, before moderating on Sunday afternoon and Monday.

The dramatic drop in temperatures comes amid a relatively mild winter in much of Eastern Canada.

"For all those people who were praying and hoping and begging for winter weather, maybe it's arrived with a bit of an extreme," Phillips said. "In Toronto, for example, we broke a record this morning: -26 C … the coldest Feb. 13 on record."

While the past two winters saw sustained periods of cold, Phillips said this winter has seen occasional but extreme dips in temperature.

"This moment here in Toronto was colder than any moment in the last two years," he said. "The real difference, though, is the duration. This is a two-day or three-day wonder. It's not going on for week after week like we saw the last two years."

Not all of Canada woke up to winter weather on Saturday, however.

In Western Canada, temperatures remained warm. In Calgary, where temperatures hovered around 6 C Saturday, a group dusted off their baseball gloves for an annual outdoor baseball tournament.

Lac Benoit, Que., clocked the coldest temperatures in the country on Saturday morning, coming in at a chilly -46.3 C. Meanwhile, Esquimalt Harbour, B.C. enjoyed a balmy high of 10.1 C.