Professional Observation
Basic Information
Observation Details
Observation Date:
December 16, 2021Submitted:
December 16, 2021Observer:
Josh Feinberg | Key ObserverZone or Region:
Mammoth LakesLocation:
Sherwins - Mammoth RockSigns of Unstable Snow
Recent Avalanches?
None ObservedCracking?
None ExperiencedCollapsing?
None ExperiencedKey Points
-Moderate snowfall beginning last night and strong winds continued until 2pm even at low elevations (way longer than forecast called for).
-Dense wind deposits found even at the lowest elevations. ECTP with moderate force in one area where I dug a pit just below Mammoth Rock at 8900′ on a NW aspect. Total snow depth 1.5-2 meters.
Hard to assess actual snowfall amounts as no where was really sheltered today and either wind was stripping snow or depositing.
-When snow stopped and skies cleared a bit, could still see ridge top winds billowing snow down the upper northerly facing slope of the Sherwins.
-No basal facets detected until over 9200′.
-Dug a pit in the deeper forest at 9400′ aiming to look and test the basal facets, the one ECT test I did only had some non-propagating failures in the new snow, and no failure deep down on the relatively thin facet layer at this one spot. I wouldn’t put much weight on this one result though….
Advanced Information
Weather Summary
Cloud Cover:
OvercastWind:
StrongSnowpack Observations
From the end of Old Mammoth Rd skinned up past Mammoth Rock and then along the ridge to 9450′ to big cliff band and decided not to push across under the steep open face that would have been necessary to cross to gain more elevation, and headed back down into the deeper forest. Wind effects throughout leading to dense surface snow, even in the deeper forest, which kept the skis on the surface with not more than 10cm of penetration (consistent turns, perfect dense wind packed snow for early season to keep the obstacles sealed-up below for the most part :-).
Didn’t venture too high today to check out the ridge top wind slabs, which I feel pretty confident would have been sizable and sensitive.