Avalanche Primer and Winter Safety
AVALANCHE
FACTS
- Most avalanches occur on
slopes of 30 to 45 degrees, but large ones can occur on slopes as little as 25
degrees.
- Snow is most unstable after
and during snowfalls or prolonged heating by the sun, especially on steep
inclines.
- Sunballs and cartwheels on the
surface during a warming period could indicate instability in deeper
layers.
- The most dangerous avalanches
usually occur on convex slopes.
- Avalanches can take place on
short slopes as well as long ones.
- Leeward slopes are dangerous
because wind-blown snow adds depth, creating hard, hollow sounding wind
slabs.
- South-facing slopes are most
dangerous in the spring.
- Smooth grassy slopes are the
most dangerous spots, but avalanches can start among trees under conditions of
stress.
- Avalanche danger can vary
within a slope.
- Following an old track does
not necessarily mean a slope is safe.
- Down-slanting trees and brush
indicates previous avalanche launches.
- Sun crust on old snow can
cause new snow to slide off.
- Rough surfaces generally favor
stability of new snow cover.
- Loose underlying snow layers
are more dangerous than compacted ones.
- Recent avalanches indicate
dangerous conditions.
- Snow falling at the rate of an
inch or more per hour increases avalanche danger.
- Snow crystals in the shape of
needles and pellets result in more unstable snow conditions than the typical
star-shaped snowflakes.
- Snow saturated with water can
avalanche, especially on south facing slopes and beneath exposed
rock.
- Rapid changes in wind,
temperature and snowfall cause changes in the snowpack and may affect
stability.
- If the snow cracks and the
crack runs as you step, the danger of slab avalanche, the most serious type of
winter hazard, is high.
- Gullies are many times more
hazardous than open slopes because they act as natural avalanche
chutes.
WINTER SAFETY
HYPOTHERMIA is called
exposure by the news media. It is a lowering of the inner body core temperature
beyond where you can not produce enough heat to stay alive. Dress with adequate
clothing when going skiing that will insulate you from the cold. Use materials
that will keep you warm even if you get wet.
FROSTBITE, or freezing of
the tissues, usually affects the toes, fingers, and face. It occurs when your
extremities lose heat faster than it can be replaced by circulating blood. It
may occur from direct exposure to cold or high wind. Damp feet may freeze
because moisture conducts heat rapidly away from the skin. Without activity the
blood circulation to the extremities is reduced, accelerating the freezing
process. With adequate equipment and clothing frostbite is not likely to occur.
Prepare for extreme conditions when planing backcountry ski trips. Take a first
aid class to prepare yourself for emergencies.
SNOW BLINDNESS is caused
by failure to use adequate eye protection during bright sunshine on snow or
light colored rock. The eyes are bloodshot, feel irritated and full of sand.
Apply a cool wet compress to the eyes. Then wear two pairs of sunglasses.
Aspirin helps the pain. Recovery may take two or three days... Snowblindness is
not a permanent condition.
SUNBURN can be prevented
by using sun screens. When you are at high altitude and on snow, cover yourself
for protection from the sun's rays. Lips are vulnerable use special caution to
protect them. Reflection from the snow can burn under the chin, around the
eyes, inside the nostrils and ears, and even the roof of the mouth. Wear a hat
to prevent scalp burns. Aspirin may be taken for pain, and drink liquids to
replenish body fluids.
ACUTE MOUNTAIN SICKNESS
can occur when a person ascends rapidly to an altitude higher than he/she is
accustomed. Their body does not adjust to the new conditions. Breathing becomes
more rapid to obtain more oxygen from the thinner air. Symptoms are loss of
appetite, headache, weakness, apathetic, nauseated, dizzy and sleepy. Try to
acclimatize, by spending time at altitude before exercising or exerting
yourself. Rest with forced deep breathing to obtain more oxygen will help.
Consume simple sugar such as; candy, oranges, or fruit juice.
WINTER
DRIVING
Chains are mandatory (make sure
they fit your tires), as is the knowledge of how to put them on. Instructions
should be in the box the chains come with, or you can pay the chain installers
to put them on. Note that chains have a proper starting end. Remember to attach
the rubber tighteners. Do not drive more than 30 m.p.h. with chains on.
Accelerate slowly and give yourself plenty of room between you and the car in
front of you. Always have the car anti-freeze (and windshield washer
antifreeze) checked before going into freezing temperatures. Other items to
carry are jumper cables, flares, small shovel, flashlight, and a tow chain.
Extra food and blankets are a good idea also. |