Observation: Public
Observation Details
Name:
Enji CooperObservation Date:
December 3, 2020Submitted:
December 4, 2020Zone or Region:
Snoqualmie PassActivity:
XC Skiing/SnowshoeingLocation:
Humpback MountainSigns of Unstable Snow
Did you see shooting cracks?
Yes, IsolatedDid you experience collapsing or whumpfing?
NoObservations
A group of 3 snowshoers ascended up the the ridge using a modified version of the climber's trail towards the Humpback Mountain summit early on Thursday morning (05:30). All of the snow below 4.5k' (at below treeline, lower near treeline terrain) was either completely consolidated, or punchy.
Snowpack above 4.5k' started showing signs of instability.
Hand shear test around 4.9k' showed localized/diffused breaking, which caused the group to take the most conservative summit approach option, which was to push up the ridge, as opposed to sidehilling across the ridge. If the hand shear test had broken in a more slab-like manner, the group would have turned around, however, .
There are several low coverage points where folks have punched all the way through boulders; otherwise, booting it would have been a better option.
Media
Advanced Observations
Observed Avalanche Problem #1:
Wind SlabComments:
Noticed wind slab behavior on all aspects of ridge above 4.5k', which covered up dry loose powder layer.Broke top layer with snowshoes with limited carbs sliding downhill across wind transported slopes.
The top-layer was 2 separate hard layers separated by hoar snow, most likely due to snowfall/wind transport, followed by a cold exposed night, followed by more wind transport.