* WHAT...Very cold temperatures as low as 40 to 55 below expected. * WHERE...Ernestine, McCarthy, and Western Copper Valley. * WHEN...Until 4 PM AKST Sunday. * IMPACTS...The dangerously cold wind chills as low as 55 below zero could cause frostbite on exposed skin in as little as 10 minutes. Frostbite and hypothermia are likely if exposed to these temperatures. An extended period of freezing temperatures could cause ruptured water pipes. * ADDITIONAL DETAILS...Temperatures will continue to fall each day. Calm winds may allow temperatures to drop to 55 to 60 below in some areas Saturday and Sunday.