Maine’s top health official warns residents to avoid prolonged exposure to the frigid conditions.

Maine’s top health official warned residents Friday to avoid exposure to the extreme cold that’s gripping the state.

Sheila Pinette, director of the Maine Center for Disease Control and Prevention, issued a health alert about the potential for frostbite and hypothermia, the two most common medical emergencies related to bitter cold.

The temperature was 3 below zero in Portland at 7 a.m. Friday, according to the National Weather Service. The average high for Portland on the date is 31 degrees.

It was 11 degrees below zero Friday morning in Caribou, and 15 below in Sanford, according to the weather service.

The forecast calls for a slight warm-up Saturday, to about 32 degrees in Portland. But the trend for the next week will continue to be below-normal temperatures statewide, the weather service says.

So far, this winter has been the coldest since the winter of 2002-03, according to weather service data.

Pinette urged Mainers to avoid prolonged exposure to the cold and watch for signs of frostbite and hypothermia.

Frostbite occurs when skin and underlying tissues freeze. The hands, feet, nose and ears are most susceptible. Signs of frostbite include skin that is white or grayish-yellow, very cold and has a hard or waxy feel. Frostbitten skin may itch, burn or feel numb.

Anyone experiencing frostbite should get out of the cold and gradually warm the affected area.

Hypothermia is a potentially dangerous drop in body temperature. Confusion and fatigue can set in, making it difficult to understand what’s happening or make intelligent choices to get to safety.

Hypothermia requires medical attention, according to the CDC. Anyone affected should be moved to a dry, warm place and warmed with extra clothing or blankets. Drinking warm liquids can help, but not alcohol or caffeine, which speed up heat loss.