Here’s the wind chill chart. Notice the four shadings, indicating how long it will take for frostbite. When we get to wind chills of -35 degrees or colder, frostbite can occur in just 10 minutes. Even in the “not as cold” areas of lower Michigan we could get frostbite within 30 minutes.

Wind chills will bring the feeling of negative temperatures between -15 and -25. Wind gusts on Thursday morning were reaching into the 40 mph range.

An extreme polar vortex moving from the Arctic across North America is expected to arrive in Quebec by Friday and persist through the weekend, according to Environment Canada.

Extremely cold air is going to take over Michigan, as the center of the Polar Vortex drops far south. The center of this swirling vortex will come as far south as Lake Superior. When the center of the Polar Vortex is so close to Michigan,

After this weekend's snow storm moves out, cold Arctic air will move in.

It exists all the time, but it usually gets stronger in winter. When the jet stream (a river of wind) bends and dips south, the edge of the polar vortex can wobble or stretch. That can let Arctic air slide into the United States and Canada and bring a short spell of extreme cold.

"Bitter cold could linger through the end of the month," the Weather Prediction Center said in an update on Monday.

A chilling polar vortex is set to bring snow and ice to the South and East this week. We show where.

The polar vortex will engulf much of North America as we head into next week, with temperatures dipping down into the -20s and -30s in some Canadian provinces. Even states like the Carolinas, Georgia, and as far as Florida will see temperatures drop below ...

It is there year round, but weakens during the summertime and strengthens in the winter.