This past Thursday, Feb. 3, I had to take a trip to west central Minnesota. When I left Duluth, the temp was -17F. As I traveled west, the thermometer in my car started reading even colder temps, with the lowest reading at -32F. The cold, dense air created a thermal inversion which blocked warmer air from rising. This effect was best illustrated by the smoke from wood fired boilers rising about 30-40 feet above ground and stopping as though it had hit an invisible ceiling. If you were to travel further north, you could have experienced even lower temps, some lower than -40F.
Northern Visions Media 