|Location:||Upper Willow Creek|
Route & General Observations
Palmer side > Upper Willow Creek
|Trigger||Natural||Avalanche Type||Cornice Fall||Aspect||Northwest|
|Elevation||4400ft||Slope Angle||unknown||Crown Depth||20in|
Observer reports a cornice failure triggering a slab avalanche.
No involvement, nobody caught.
Obvious signs of instability
|Recent Avalanches?||Yes||Collapsing (Whumphing)?||Yes||Cracking (Shooting cracks)?||No|
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.
Patches of clearing with clouds late in the day.
Moist, heavy new snow.
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.