An extreme cold warning was released by the National Weather Service on Thursday at 12:41 p.m. valid from 7 p.m. until Friday 1 p.m. for Jefferson and Lewis counties. Frostbite can occur in 15 minutes or less with apparent temperatures of 25 below zero or colder.”Understanding cold weather alertsExtreme cold warning: Take Action! An extreme cold warning is issued when dangerously cold air temperatures or wind chill values are expected or occurring. An extreme cold watch is issued when dangerously cold air temperatures or wind chill values are possible. A cold weather advisory is issued when seasonably cold air temperatures or wind chill values, but not extremely cold values, are expected or occurring.