Avalanche

Avalanche is huge mass of unstable snow, ice or debris that set down in motion from a particular point due to various factor.

Formation of Avalanche: Avalanche can form due to various factors as mentioned below

1.       Nature and contour of the terrain: Angle, aspect ratio and configuration of the terrain can affect the formation of the avalanche. Avalanche is frequently formed between the angle of 25-60 degree slope of the terrain.
2.       Nature of the snow i.e. soft or hard-pack
3.       Temperature: The sudden variation of temperature can make the layers of ice to slide easily and so contribute for the formation of avalanche. Or, increase in temperature typically in daytime can break the cornice and cause avalanche
4.       Failure of mechanical equilibrium like vibration, weight: Unstable cornice or slight movement in ice/snow due to vibration can cause the formation of the avalanche

Powder snow avalanche

Types of Avalanche: Surface and Ground avalanche

Principal Types of Avalanche:

1.       Powder snow avalanche
2.       Fresh wet snow avalanche
3.       Wet snow avalanche
4.       Snow slab or packed snow avalanche
5.       Cornice avalanche

Guidelines for mountaineer in dealing with avalanche

1.       Watch vital weather warning signs:

a.       Heavy recent (in past 24 hrs) snow falls

b.      Prolonged period of very warm or very cold weather

c.       Wind loading on lee slopes

d.      Strong solar warming

2.       If need to cross avalanche prone area:

a.       Do not go alone in avalanche area

b.      Negotiate the safest route and slope

c.       Keep walking from the ridge and possibly stay away from cornice

d.      Walk zigzag on snow slope – do not walk diagonally

e.      Appoint a look-out person to watch all other mountaineers crossing an avalanche prone area

3.       Other general tips:

a.       Use equipments like Avalanche cord, Avalanche Victim Detector (AVD)

b.      Maintain silence

c.       Unbuckle rucksack

d.      Keep distance 50-100m with other mountaineer

e.      Cover mouth and nose with a cloth to avoid inhale the soft snow

4.       When caught under avalanche

a.       Try to swim on the moving avalanche snow

b.      Take cocoon position to cover face with hand and do not panic