CHICAGO — A whirlpool of frigid, dense air known as a "polar vortex" descended Monday into much of the U.S., pummeling parts of the country with a dangerous cold that could break decades-old records with wind chill warnings stretching from Montana to Alabama.
For a big chunk of the Midwest, the subzero temperatures were moving in behind another winter wallop: more than a foot of snow and high winds that made traveling treacherous. Officials closed schools in cities including Chicago, St. Louis and Milwaukee and warned residents to stay indoors and avoid the frigid cold altogether.
The forecast is extreme: 32 below zero in Fargo, N.D.; minus 21 in Madison, Wis.; and 15 below zero in Minneapolis, Indianapolis and Chicago. Wind chills — what it feels like outside when high winds are factored into the temperature — could drop into the minus 50s and 60s.
"It's just a dangerous cold," said National Weather Service meteorologist Butch Dye in Missouri.
It hasn't been this cold for almost two decades in many parts of the country. Frostbite and hypothermia can set in quickly at 15 to 30 below zero.