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2torial #0743:
Learn2 Avoid Frostbite
Understand frostbite
Your body is reacting (perhaps overreacting, in
some cases) to the dropping of its core
temperature (see Keywords). If an effort to
reduce heat loss, it constricts the blood vessels
in the extremities. This allows more blood to
circulate in the core of the body (thus maintaining
its temperature), but this action deprives the
extremities of the warming effect of blood
circulation. Without that support, fingers, toes,
ears, and noses can't sustain proper body
temperature, and eventually start to freeze.
So you can think of frostbite as a failure of
blood circulation. Blood and other fluids in the
affected area thicken and congeal as the
temperature of the tissue drops. Warm blood from
the rest of the body, which would normally maintain
the proper body temperature, can't pass through the
frozen tissue. If the tissue remains frozen long
enough (as in severe cases of frostbite), the cells
in the tissue will die, and the injured area will
turn black and fall off.
Frostbite can develop in three distinct stages
that are roughly similar to burn degrees:
frostnip, which is not actually frostbite;
superficial frostbite, and deep
frostbite. Here's how to recognize them:
- Frostnip: This is the mildest form of
cold injury (it's not actually frostbite). It
usually appears on the ears, nose, or cheek as a
whitish, waxy-looking patch of skin. This is
commonly happens in situations with severe cold
and wind chill (see Keywords), when the affected
part is exposed for even a few minutes.
Immediate warming of the area (fingertips placed
under the armpits, for example) often results in
a complete recovery. The area will become red
and painful, feeling as if it were burned, and
may blister.
- Superficial frostbite: When
frostnipped skin isn't warmed up, it'll often
develop into superficial frostbite. At this
stage, the tissue under the skin has begun to
freeze and will appear white and bloodless,
although it'll remain soft and pliable when you
touch it. Frostbitten tissue will often develop
large blisters a day or so after the exposure;
these blisters will harden and turn into eschar,
a thick, black scar tissue that takes a few
weeks to be replaced by new skin.
- Deep frostbite: This is a serious
condition which occurs only in extreme climatic
conditions: usually at high elevations or near
polar caps. In this case the soft tissue below
the skin freezes solid: the area turns deep red
or purple, feels cold to the touch but itself
has no sensitivity remaining. Deep tissue damage
results, possibly leading to amputation.
Fortunately the occurrence of deep frostbite is
quite rare for the average outdoor enthusiast.
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