Mountaineering Club
Avalanche Awareness

  1. Avalanche Types
    1. Loose Snow Avalanches
      (point avalanche)
    2. Slab Avalanches
  2. Point Avalanche Development
    Point avalanches start with a small amount of cohesionless snow
    and generally picks up more snow during the descent. Often
    associated with wet loose snow.
  3. Slab Avalanche Development
    1. Terrain
    2. Weather
    3. Snow Pack
  4. Terrain
    1. Slope Angle
      • 30 - 45°
    2. Slope Orientation
      • Lea, wind-loaded slopes
      • Cornice roofs
      • North-facing slopes
      • South-facing slopes
    3. Roughness, Shape, and Vegetation
      • Boulders vs. grass
      • Convex slope
      • Sparse vegetation
      • No uphill branches
  5. Weather
    1. Precipitation

1.      Type

2.      Amount

3.      Duration

4.      Intensity

5.      Wind

1.      Direction

          • Lea deposition zones

2.      Speed

3.      Duration

6.      Temperature

0.      Air temperature

1.      Snow temperature

2.      Solar reradiation

          • Cloud cover
          • Moisture content of snow pack
    1. Snow Pack

0.      Stratigraphy

1.      Bonding

2.      Shear Strength

    1. Stability Evaluation

0.      Recent avalanche activity

1.      Whumphing noises

2.      Shooting cracks

3.      Recent wind loading

4.      Hollow sounding snow

5.      Snow pit

    1. Snow Pit Tests

0.      Identifying layers

1.      Hardness tests

·  Fist

Very soft

·  Four fingers 

Soft

·  One finger

Medium

·  Pencil

Hard

·  Knife

Very hard

 

 

2.      Shear Test

    1. Routefinding

0.      Broad valleys

1.      Ridge tops

2.      Dense forests

    1. Equipment

0.      Transceivers

1.      Shovel

2.      Probe poles

    1. Safe Travel In Avalanche Terrain

0.      Good communication

1.      Safe route

2.      Escape route

3.      Cross-unstable areas one-at-a-time.
Stopping only in protected locations 

    h.                    

References:

    1. The Avalanche Handbook
      David McClung & Peter Schaerer
      The Mountaineers
      1011 SW Klickitat Way, Seattle, Washington 98134, 1993
    2. Snow Sense
      A Guide To Evaluating Snow Avalanche Hazard
      Jill Fredston & Doug Fesler
      Alaska Mountain Safety Center, Inc. 9140 Brewsters Drive, Anchorage, Alaska, 99516, 1994