Page 11 - 2000 AMA Millenium

leering Trips’
Cold injury occurs when body tissues freeze and ice crystals form between cells usually at extremities.
• Care in choice of appropriate clothing essential since prevention is again better than cure.
• Three categories of frostbite:
1 Frostnip - skin blanches and becomes numb in affected area. Reversible changes to tissues that tingle and ache on re-warming (“hot aches”). Treat immediately shelter, re-warm affected part using other parts of body.
2 Superficialfrostbite - only skin and surface tissues frozen which is soft and pliable when pressed. After re-warming tissue may become blue/purple, hurt and swell. Blisters and black carapaces may form.
3 Deep frostbite involves deeper body structures, e.g. muscles, bones, tendons. Permanent tissue loss inevitable.
Treatment for 2 and 3; re-warming in water in 42”C to 44“C range. Do not rub tissue.
PREPARATIONS
Time and effort spent on these can save valuable time and effort on the hill. Special attention should be paid to clothing, equipment, mountain weather watching, food and dnnk, getting fit, route planning, snow and ice structures and habits.
Clothing
Primary function ofclothing is the prevention ofheat loss from the body. Maximum insulation gained from a series of layers in which and between which air is trapped. Winter mountain climate demands water-proofing, wind proofing and moisturetransmission from clothing. Modern “base layer” material with vapour proper­ ties surprisingly comfortable and effective. Polartec fleece mid layer garments have high insulation properties and breathable fabrics make good ‘shell layers’. Don’t forget your feet, hands and head. Loop-stitch socks, polartec finger gloves and waterproof fleece-lined mittens, waterproof fleece-lined head cover.
Equipment.
• Make sure you have appropriate personal and technical equipment for your planned route and know how to use it.
• Make sure each party member has a map and compass for safety.
Mountain weather watching
• Trace recent weather system tracking through your chosen area, i.e. (newspaper synoptic charts)
• Obtaining up to date forecast can be a key factor in the outcome of a mountain day.
• Remember ground level forecasts need modifying for high mountains. Altitude, aspect, wind direction and strength must be incorporated.
• Access sources of weather forecasts - radio, newspapers, TV, telephone or fax.
Food and drink
• Food provides the winter mountaineer with the energy required for ‘basal metabolism’, physical activity and the cold conditions totalling about 15,00017,000 kilojoules per day.
• Regular snacking on the hill (before the onset of hunger) is better than a prolonged stop in cold conditions.
• Food is better stored inside the body than in the rucsac!
• About 2.5 litres of water is lost from the body during a winter
mountain day that needs to be replaced over time.
by Lt Roger S.D. Smith MIC
• It is impractical to replace all this volume on the hill so copious drinks before setting out would be desirable.
• Generous carbohydrate intake helps the body to store liquid in
the muscles.
• Regular adjustment to clothing and energy output is needed to
minimise sweating but maintain warmth.
• Dehydration and overheating are possible on a winter mountain
day.
Getting fit
The most effective physical preparation for winter mountaineering is mountaineering in winter! If denied this then a suitable training programme - closely replicating the intended activity - should be followed.
• Such a programme should include elements of STAMINA, STRENGTH and SUPPLENESS.
• Long walks in the lowlands near home and night navigation in home locality are good training for winter mountain walking.
• Winter crag climbing and cross-country' running are good
training for mixed winter climbing.
Route planning
• Time spent studying a proposed route and preparing a route plan
is time well spent.
• Apply Naismith’s Rule and Tranter’s Variations to proposed
route.
• Construct a route profile which helps build up a 3-D picture of
the proposed route.
• Plan approach and descent routes to unfamiliar locations.
Snow and ice structures and habits
• There are many forms of precipitation in winter.
• The fate of the snowflake - settling, ET met, TG met, melt-freeze
met, wind transport, water-infiltration, surface crust and
hoaring, convection and evaporation.
• Types of snow (Eskimos have over 50 words for snow). We need
to be aware of powder snow (loose unconsolidated), wind slab (pulverised snow flakes deposited on lee slopes), firm or settled snow (old well-bonded) and Neve (made of large crystals (formed by MF met) ideal crisp snow for walking/climbing.
• Types of ice. White ice - derived from néve by MF met; Blue ice - comes from drainage water mixed with snowfall; Water ice - comes directly from water, e.g. icicles and organ pipes; Black ice - only forms at extremely low temperatures extremely hard. Verqlas is a surface skin of water-ice on rocks, etc. and ice crust- caused by MF met on surface layers of snow.
• Remember that the same slope will change in character as snow- pack constantly changes through the season - no area/route is ever the same!
• Snow bridges over streams can be a hazard.
• Boulder fields can be a nightmare when snow choked.
• Cornices form on many edges and present problems when
approached from any direction.
• Avalanches - snow slides of one layer of snow over another or the
whole snow pack over underlying ground. They are not
uncommon in Scotland.
• Assess the avalanche risk of slope by digging snow pit(s) and
carrying out shear test, establish hardness and wetness of layers in profile. Remember that the greater the physical difference between adjacent layers the greater the chance of sliding. Try compressing columnArlock of snow from above (Rutschbock)
• Slopes of 30°- 45” most vulnerable, fewer avalanches above 60' and below 20”.
• Avoid convex slopes (look for uniform or concave slopes wherever possible) and narrow confined runnels.
Army Mountaineer
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