While some parts of Colorado have been experiencing a warm up over the last week, others will be returning to negative degree wind chills on Friday, according to the National Weather Service (NWS). 

According to the service, areas including the Central Yampa River Basin and Upper Yampa River Basin could record wind chills as low as -20 degrees before 11 AM on Friday. 

Wind chill is determined by current temperature and wind speed. Winds can dramatically change the way cold feels to the body, also increasing the risk of frostbite and hypothermia. 

At temperatures this cold, frostbite could occur in as little as 30 minutes, according to the service. 

Click here for a more in-depth look on how wind chill is calculated and how wind can speed can shorten the time it takes for frostbite to affect the body. 

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