Its typical consequences aren’t nearly as severe for Sierra enthusiasts as those of the avalanche or blizzard, but frostbite is an ever-present danger of the snow season.

Frostbite’s symptoms may be subtle at first: a slightly painful, prickly or itching sensation; skin that turns red, white, pale or grayish-yellow; numbness; and clumsiness due to joint and muscle stiffness.

The signs of frostbite should not go ignored. Winter campers and backcountry hikers run a particular risk of developing frostbite if they do not take proper protective measures.

Frostbite usually affects smaller or exposed areas of the body, such as fingers and the head. Because of numbness, a person may not realize he or she has frostbite until it’s pointed out by someone else.

Frostbite does not occur at once but in several stages.

• First stage: Frostnip. a mild form of frostbite in which skin turns red and feels very cold. Continued exposure leads to prickling and numbness in the affected area.

• Second stage: Superficial frostbite. Reddened skin turns white or very pale. The skin may remain soft, but some ice crystals may form in the tissue. Skin may begin to feel deceptively warm – a sign of serious skin involvement. If treated at this stage, the skin surface may appear mottled, blue or purple as it’s warmed or thawed. a blister may appear 24 to 36 hours after rewarming the skin.

• Third stage: Severe frostbite. As frostbite progresses, it affects all layers of the skin, including underlying tissues. a deceptive numbness can cause a loss of sensation of cold or pain.

Joints or muscles may no longer work. Large blisters form 24 to 48 hours after rewarming. After that, the affected area turns black and hard as the tissue dies.

When frostbite symptoms appear, such as skin color change or a loss of sensation in the affected area, a person should seek medical attention immediately.

WATCH OUT FOR TREE WELLS

• Tree wells are generally found in the deep snow of ungroomed areas. You must also be careful next to trees at the edges of groomed trails.

• Particularly dangerous trees are firs that have their lower branches touching the snow surface.

• Be cautious near any tree in the snow. there is no easy way to identify by sight whether a particular tree has a dangerous well. The branches often block visibility of the hole that could become a trap.

• Prevention of falling into a tree well is all-important because the odds of surviving deep snow immersion are low.

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