I asked my grandkids this morning: what do you think of when you imagine intense cold like we have today (-22 F at 7 a.m. this morning) ? They said — white, blue, partially transparent — sort of like this.
White and blue, slightly purple colors at sunset 4:30 p.m. in St. Paul MN – temperature -12 F
Intense cold makes interesting patterns of white, slightly transparent ice crystals on the insides of our windows.
Sunrise after snowfall at -22F, white and blue with a tinge of pink-purple.
Blowing snow on Lake Harriet, Minneapolis on Jan 26 2013, windchill temperature -43 F. White, white, and more white. (Star Tribune photo by Jeff Wheeler)
But weather forecasters reserve the color purple for the really intense cold.
Weather map for North America for Jan. 27, 2013.
Brrrr…. send that polar vortex back to Alaska!