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Observations

Region: Hatcher Pass
Location: Upper Willow Creek
Observer:
Date:

Route & General Observations

Palmer side > Upper Willow Creek

Avalanche Details

Avalanche details

Trigger NaturalAvalanche Type Cornice FallAspect Northwest
Elevation 4400ftSlope AngleunknownCrown Depth 20in
Width 300ftLength 500ft  

Observer Comments

Observer reports a cornice failure triggering a slab avalanche.
No involvement, nobody caught.

Red Flags

Obvious signs of instability

Recent Avalanches?YesCollapsing (Whumphing)?YesCracking (Shooting cracks)?No

Observer Comments

This group felt a large collapse while sitting on their machines in the flats. This occured at a separate time from the avalanche, but is consistent with other reports. Collapsing is a bulls eye clue for ripe avalanche conditions.

Weather

Weather

Patches of clearing with clouds late in the day.

Snow Characteristics

Snow surface

Moist, heavy new snow.

Forecaster Comments

Forecaster Comments

It is important to remind ourselves that we can trigger avalanches from well below slopes, even from the flats. Collapsing has been observed by numerous people, and it is the act of collapsing the snow, even in the flats, which can travel like a wave under the snowpack up steep slopes, triggering avalanches above. Sound form a snowmachine can not trigger avalanches, but may appear to if we do not understand the mechanics of snow failure. In this case it may have been a cornice failure that triggered the avalanche.

Photos & Video

Photos



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