* WHAT...Very cold wind chills of 30 below to 40 below expected. * WHERE...Northern Copper River Valley and along the Tok Cutoff. * WHEN...Until 3 PM AKST this afternoon. * IMPACTS...Frostbite and hypothermia are likely if exposed to these temperatures. Wind chill values can lead to hypothermia with prolonged exposure. Very cold temperatures can lead to hypothermia with prolonged exposure.