Observation: Hatcher Pass

Location: Eldorado Test Slopes

Route & General Observations

IMB parking lot to Eldorado test slopes to north ridge of Skyscraper.



Red Flags
Red flags are simple visual clues that are a sign of potential avalanche danger. Please record any sign of red flags below.
Obvious signs of instability
Recent Avalanches?No
Collapsing (Whumphing)?Yes
Cracking (Shooting cracks)?Yes
Observer Comments

Poor structure in the snowpack was observed to be widespread, but spatially variable. One collapse/whumph and shooting crack was observed by another traveler above us nearing the top of the north ridge ascent on Skyscraper. No avalanche was triggered, however, this is as close as you can get to triggering an avalanche without actually doing so. This location was suspect due to recent patterns. Patterns for suspect areas are upper elevation ridgelines, leeward to recent wind events, and stiff snow overlying weaker snow.
Other than this one collapse and shooting crack we observed no other collapses or shooting cracks on our tour.

Weather & Snow Characteristics
Please provide details to help us determine the weather and snowpack during the time this observation took place.

Broken skies trending towards Obscured
12deg F

Snow surface

Slowly faceting snow surface
Wind loaded areas tend to have a mixture of a few inches of soft snow over hard, supportable slabs and soft deep snow. Within a short distance (20 horizontal feet) from the upper portion of the snowpack, the snowpack can change from 1F hard with ski penetration 4", to F hard with ski penetration 1 foot.


Slabs in the upper snowpack are sitting on weak, faceted grains which are metamorphosing into larger grains over time and becoming a weaker buried persistent layer. Varied propagation results in stability tests appear to be related to the varying cohesiveness of slabs, spatial variability, and a low level of continuity. Weak layers appear to be widespread with a high level of continuity.
Where slabs are 1F hard we are seeing impressive propagation results with many tests yielding propagation failure at PST 30/100 END and moderate ECTP's. This is also where we are observing whumphing and sometimes shooting cracks.
Where slabs are softer, 4F or less, results are averaging PST 30/100 SF and moderate ECTN's. Of note, these areas have not be producing whumphing and/or shooting cracks.

Photos & Video
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