Observation: Public
Observation Details
Name:
Josh HirshbergObservation Date:
December 24, 2020Submitted:
December 25, 2020Zone or Region:
Stevens PassActivity:
Skiing/SnowboardingLocation:
Lichtenberg MtnObserved Avalanches
Did you observe any avalanches?
YesAvalanche Type:
Soft SlabSize:
Size 3: Could bury and destroy a car, damage a truck, destroy a wood frame house, or break a few treesElevation:
5600Aspect:
SEComments:
All on Lichtenberg E Peak- natural, slab avalanches, running in old snow (Dec 12th FC). These occurred on the night of Dec 19th or early on the 20th4 crowns on the SE face and gullies 52,00-5,600ft- D2.5-3
1 crown on the SSW shoulder, 5,000ft- D2
Signs of Unstable Snow
Did you see shooting cracks?
Yes, IsolatedDid you experience collapsing or whumpfing?
NoObservations
We found challenging travel conditions both up and down due to a firm sub-service crust and variable surface conditions. Steep solar aspects had very light sun affect which only stiffened the surface snow and wasn't strong enough to form a crust. Exposed slopes had drifts from W wind on the 21st. These were staying reactive longer than usual due to the slick 12/21 crust and overlying facets that the slabs were resting on. It was easy to get cracking and mini-avalanches on test slopes and small pockets of wind slab.
A profile at 5,000ft SSW revealed weak snow on the surface including; surface hoar, near-surface facets, and the Dec 21 facets (0.5-1.0mm) which are 15-25cm below the surface on a stout crust. The Dec 21 rain event has transformed much of the old snow structure in the mid to lower half of the snowpack and most of the snowpack was either moist or frozen melt forms. Surprisingly, the Dec 12th weak layer was still quite weak and produced repeatable tests indicating propagation.
Media
