At 12:28 a.m. on Friday, the National Weather Service issued a cold weather advisory valid from 11 a.m. until Saturday 10 a.m. for Carbon and Monroe counties. The weather service states, "Very cold wind chills as low as 15 degrees below expected." "The dangerously cold wind chills as low as 20 below zero could cause frostbite on exposed skin in as little as 30 minutes. Understanding cold weather alertsCold weather advisory: Be Aware. A cold weather advisory is issued when seasonably cold air temperatures or wind chill values, but not extremely cold values, are expected or occurring.