Observation: Public
Observation Details
Name:
Nate Hough-SneeObservation Date:
February 27, 2021Submitted:
February 27, 2021Zone or Region:
East CentralActivity:
Skiing/SnowboardingLocation:
DoctoriaTriggered Avalanches
Did you trigger any avalanches?
YesWas it intentional?
NoAvalanche Type:
Hard SlabSize:
Size 2: Could bury, injure, or kill a personElevation:
5400Aspect:
NEComments:
Avalanche One: The slope released as a wind slab (crown to 75cm, avg 45 cm) for the second skier following an aggressive ski cut to the left. The terrain was a 5400' rollover in cross-loaded terrain from easterly/southeasterly downslope winds and westerly frontal winds. The slope didn't release until third turn under foot and the skier was able to maintain speed and quickly exit skiers left to a safer, lower-angle slope. The ensuing slide continued 200' down (HS-ASu-R1-D1.5). Crown was 100' wide and failed on surface hoar over subtle scour/wind crust (est. Wednesday 24 Feb 2021). The slope angle was <28 degrees with a subtle rollover to 32-35 degrees. Avalanche Two: An aggressive ski cut appeared to not release the slope above a convex rollover from 30 to 36 degrees. As the skier initiating the cut slowed, the slope broke, the skier stayed on his feet and hopped upslope of the fracture as the slide drained the feature. The crown was up to 100cm and averaged 75cm and the slide ran 400-500' below (HS-ASc-R2-D2). This slide occurred later in the day at 5400' on an adjacent cross-loaded NE slope after more wind had occurred throughout the day.Observed Avalanches
Did you observe any avalanches?
YesAvalanche Type:
Hard SlabSize:
Size 3: Could bury and destroy a car, damage a truck, destroy a wood frame house, or break a few treesElevation:
MultipleAspect:
EComments:
Multiple natural hard slab avalanches since Thursday 25 Feb 2021 at all elevations, mostly D2. These occurred at all elevation bands and all seem to have become reactive following the 25 Feb 2021 storm and 26-27 Feb 2021 wind events. These large, destructive, and unsurvivable avalanches may have failed on any number of recent or less recent interfaces, including the January facet-crust combination. In some cases, the weak layer may be recent surface hoar (24 Feb 2021) overloaded by strong winds that were building deep slabs today.Photo:
Signs of Unstable Snow
Observations
If there was any doubt that we still have a persistent and deep slab problem after recent storms that might have "flushed" or "reset" much terrain, it can be put to bed: we still have a problem in the east central zone near the Cascade Crest, and it's making itself obvious. We saw multiple avalanches from last night into today that ran on any number of weak snow layers, likely facet-crust combinations deep in the snowpack. We noted the following avalanches:
Big Slide Creek, 7000', S,
East of Victoria Creek, 4000', E/NE HS-N-R1-D2
Lower Victoria Creek 5000' W, HS-N-R1-D2
Upper Victoria Creek 6600', N, HS-N-R1-D2
Bob Creek (viewed from across valley) 5600', SE, HS-N-R1-D2
Doctoria Trees - 5400' NE HS-ASc-R2-D2 and HS-ASc-R1-D2 - these were skier-triggered avalanches with crowns to a meter deep on rapidly wind loaded slopes.
Doctoria Trees
Today we traveled in clear to broken sky conditions with cool temps form 2400' to 6400' on a NE slope generally well below 30 degrees. Winds were moderate to strong SE and W depending on topographic vs frontal winds and transport was moderate to high all day. We noted wet grains in the snowpack below 3600' and a deep snowpack around 5200' (HS 350-390cm in this wind loaded area).
We traveled cautiously, putting in a very safe, conservative skinner, but skied slopes that connected to a few steep rolls up to 35-degrees on NE terrain. We poked the bear and got away with it with two skier-triggered avalanches.
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