The counties of Carbon and Monroe were under the warning.
“The threat of extreme cold has ended,” the National Weather Service says.
Understanding cold weather alerts
Warning: Extreme cold: Act now! When dangerously low air temperatures or wind chill values are predicted or already occurring, an extreme cold warning is issued. Avoid venturing outside if there is an extreme cold warning in effect. Make sure at least one other person is aware of your whereabouts, wear layers if you must go outside, and cover any exposed skin. When you reach your destination safely, update them.
Be ready for extreme cold watch. When extremely low air temperatures or wind chill values are possible, an extreme cold watch is issued. As with a warning, change your plans so that you don’t spend the coldest hours of the day outside. Update your winter survival gear and make sure your car has at least half a tank of gas left.
Warning of cold weather: Exercise caution. When seasonably cold air temperatures or wind chill values—but not exceptionally severe ones—are anticipated or happening, a cold weather advisory is issued. When you and your loved ones go outside, make sure you cover any exposed skin and wear suitable clothing.
United Robots offers a service called Advance Local Weather Alerts that gathers the most recent information from the National Weather Service using machine learning.