Observation: Public
Observation Details
Name:
Mark AllenObservation Date:
December 25, 2020Submitted:
December 26, 2020Zone or Region:
East NorthActivity:
Skiing/SnowboardingLocation:
North Cascades-East Slopes North-Cutthroat CreekObserved Avalanches
Did you observe any avalanches?
YesAvalanche Type:
Soft SlabSize:
Size 2: Could bury, injure, or kill a personElevation:
Alpine start zones-D2s not entirely reaching Near Tree Line ZoneAspect:
NComments:
More Avalanche Obs from the Dec 21st cycle: In the Cutthroat drainage. All main N-NE facing bowls on Hinkhouse peak ran D2 leaving some debris in all the main bowl features. Never were the slides full path and only utilized portions of their start zones. In every case, the start zones have refilled and crowns are now fully buried. Crowns are also visible on steeper unsupported mid-mountain features that were thought to have sympathetically released by the avalanches from above.Photo:
Signs of Unstable Snow
Observations
Ubiquitous valley coverage of 3-7mm Surface Hoar. Luckily, this persistent grain and surface form did not grow much higher than a 100ft in el. beyond the valley floor in the Cutthroat Creek drainage. The dominate surface form observed was the recent decomposing snows from Dec 21st. I did not observe any near-surface-faceting NSF from the past few days of cold temps below 5500ft during the extreme inversion. In a Observation pit: NE 6850ft-NE Height of Snow: 140cm deep - The obs support and match other observations that the Dec 21-HST interface is down 40-55cm down and the Early-Dec crust is down 80cm. The test results are still failing 2 cm above crust. (see pit image) The results were CTH (28/29)-SP x3 and stubborn, but failing suddenly on the last few blows in every test. No other reactivity to report in the column or from travel. I too observed a thick layer of 1mm facets exists beneath the Early Dec crust (4F hardness), but it did not prove reactive, even with any small column test.
Weather: Snowing after 1:00pm on Dec 25th and increasing through the evening, cool in the morning (19) but warming as the system approached. The trees held their snow all day. Thin clouds in the morning and overcast OVC by late morning leading to obscured OBS by evening. Light winds did pick up and start transporting some at ridge crest as the low energy storm entered the drainages. Boot penetration is less since the solstice storm and around shin deep.
Mark Allen - NWAC Pro Observer East Slopes North
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