Minnesota, Dangerous cold and school closings

Blizzard warning: Kittson County, the northwestern-most county in Minnesota, is under a blizzard warning until 9 p.m. Friday.
National Weather Service meteorologists warned of temperatures cold enough to be fatal descending across most of the nation.
The National Weather Service has issued an Extreme Cold Warning for northern parts of Minnesota and a Cold Weather Advisory ...
It has to reach an air temp or wind chill of -35 to generate an extreme cold warning in the Twin Cities. In greater Minnesota ...
The NWS extreme cold warning for Duluth said: "The dangerously cold wind chills as low as 40 below zero could cause frostbite ...