The Milwaukee County Medical Examiner's office is investigating the death of an 80-year-old man who likely died of hypothermia early Sunday morning.

Milwaukee will kick off this week with the most extreme cold of the winter so far. During the coldest periods, wind chill is forecast to range between -15 and -30 degrees. That's well beyond the threshold for developing frostbite and other adverse health symptoms from cold-weather exposure.

The center at 12th and Vliet is open from 8 a.m. to 5:30 p.m. on Monday and Tuesday due to the cold. Nick Tomaro with the Milwaukee Health Department said more than 100 people took advantage of the center on day one. Darnell Bonner said on Sunday, he was rushed to the hospital for hypothermia while waiting for a shelter to open.

As wind chills hit dangerous levels, the decision to close schools becomes critical. Kevin Wagner, a lead meteorologist with the National Weather Service, explains how those decisions are made.

An "artic air mass" will be moving into the region from Canada as we head into the weekend, causing temperatures to tumble.

For those without shelter, the Milwaukee Coalition on Housing and Homelessness operates seven warming centers across the city.

A Cold Weather Health Advisory has been issued for Milwaukee County. The health advisory is in effect from 9 p.m. Sunday, Jan 19 through 9 p.m. Monday, Jan 20.