Multiple small soft slab avalanches observed, some having naturally triggered likely in the early morning hours, others triggered remotely on adjacent steep(er) terrain features as we toured through low angled terrain up towards Henry Creek/Arrowhead clear cuts. Depth measured 10-15cms, with newer storm snow from 12/20 observed to have slightly higher density than the snowfall from 12/18. Ski cuts of steeper terrain features intentionally triggered similar sized soft slabs and in some cases activated a deeper layer (12/18 interface) that was noted to contain 6-8mm surface hoar forms. Soft slab width ranged from 5 to about 30 feet. One natural on the road cut above the road just prior to crossing Henry Creek was estimated to be about 150 feet wide.
Did you observe any avalanches?
Signs of Unstable Snow
Did you see shooting cracks?
Did you experience collapsing or whumpfing?
Traveled up into Arrowhead clear cuts in search of lower angled turns. Discovered ski pen around 50cm with fairly active upper snowpack as described.
Pit at 3274' with HS 119, CTV down 10cm at interface of 12/18 and 12/20 storm snow, CT3 SP down 26cm, some graupel noted on this layer though no surface hoar observed (uncertain but this may represent interface of 12/9 and 12/18 storm snow?). Deeper in the snowpack the 11/25 crust was observed and was reactive with CT16 SC. ECTX at this pit location.
S4 for the entirety of our short tour. We stuck to lower angled terrain. The turns were good but deep, some settlement will help with improving downhill travel through lower angled terrain.
Observed Avalanche Problem #1:
North aspects, D1, touchy, skier trigger likely, 10cm down at interface of 12/18 and 12/20 storm snow. Interface of 12/9 and 12/18 storm snow was also reactive to ski cuts on small convex test slopes and was noted to contain 6-8mm surface hoar forms.