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Frostbite
Frostbite is caused by the restriction of
blood circulation due to extreme cold. The beginning of
frostbite is not necessarily painful but is seen by
telltale white spots. Cheeks, nose, and ears are the
most vulnerable. Always keep ears covered and wear a
facemask in below-freezing weather. It helps to "make a
face" to stimulate circulation.
To treat frostbite, slowly warm the affected area by
holding a warm, bare hand against it. Keep moving, find
shelter, or build a fire - but do not sit too close to
the fire. Rapid thawing of frostbite can cause
inflammation and even gangrene.
Rubbing frostbitten flesh may damage frozen tissues.
Never rub snow on frostbite.
Never drink alcohol to warm you up - alcohol restricts
blood circulation. Drink some other non-alcoholic hot
beverage instead.
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Hibernation
Many small and
medium-sized mammals in north-temperate regions solve the
problem of winter scarcity of food and low temperature by
entering a prolonged and controlled state of dormancy. True
hibernators, such as ground squirrels, groundhogs, and mice,
prepare for hibernation by building up large amount of body
fat. Some, such as the groundhog, also lays in stores of
food in their burrow. Entry
into hibernation is gradual. After a series of "test-drops"
during which the temperature drops a few degree and then
returns to normal, the animal cools to within a degree or
less of the surrounding temperature. Metabolism is greatly
reduced. In the ground squirrel, for example, the
respiratory rate drops from a normal of 200 per minute to 4
to 5 per minute, and the heart rate from 150 to 5. This
means that the body slows down In most hibernators, the body
temperature is closely checked by internal systems. If the
body temperature drops dangerously close to the freezing
point, the animal will awaken. The hibernators also awaken
at irregular intervals to eat and eliminate wastes and then
return to sleep.
Some mammals such as bears, badgers,
raccoons, and opossums enter a state of prolonged sleep in
winter with little or no drop of body temperature. This is
not true hibernation. Bears of the northern forest may sleep
for several months. Their heart rate may drop from 40 to 10
beats per minutes, but their body temperature remains normal
and the bear is awakened if sufficiently disturbed.Mammals
are not the only hibernators. There are several other
animals such as the toad and frog that survive winter by
hibernating.
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Building a Snowcave
A snow cave is very
similar to an igloo but instead of being made out of blocks
of snow, a snow cave is hollowed out of a snow bank. Snow
caves are faster to make than an igloo and the only tool you
will need is a shovel. Choose a location with a steep
hillside and deep snow. Your roof must remain at least 2
feet thick after your cave is completed. A snow cave is made
up of three parts, the main cavity of the cave, the entrance
hole and a ventilation shaft. The smaller you can keep the
entrance to your cave, the warmer the cave will stay. After
hollowing out the cave, use the handle of your shovel to add
an angled ventilation shaft to the roof of your cave. Last,
you will want to compact and smooth the snow walls to turn
the inside layer to ice. As long as your ventilation shaft
is not blocked you can use candles or a lantern to light
your cave and provide additional warmth.
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