Frostbite occurs due to the freezing of skin and underlying tissues.

According to a news release, most commonly, exposure to cold-weather conditions is the cause for frostbite. But it also can originate from very cold liquids, direct contact with ice and freezing metals. Risk increases as air temperatures fall below 5° Fahrenheit (F). In a wind chill of minus 16.6° F, frostbite can occur on exposed skin in less than 30 minutes.

Signs and Symptoms of Frostbite include:
• At first, a cold and prickling feeling;
• Numbness;
• Skin that appears red, white, bluish-white, grayish-yellow, purplish, brown or ashen, depending on the severity and normal skin color;
• Hard or waxy-looking skin;
• Poor dexterity of joints and muscles; and/or
• Blistering after warming in severe cases.

Stages of frostbite include:
• Skin not affected by cold damage has no change in texture and color.
• Frostnip is slight frostbite that disturbs the skin, causing changes to skin color and a chilled sensation followed by numbness. If treated with first-aid measures, frostnip can be prevented from permanently damaging skin.
• Superficial frostbite is when the skin feels warm. A fluid-filled blister could appear 12 to 36 hours after rewarming the skin.
• Deep frostbite will likely result in a numbness and discomfort. Joints or muscles may stop working. Large blisters will form 24 to 48 hours after rewarming, as well as tissue will turn hard and black as it dies.