| Recent Avalanches? | No |
| Collapsing (Whumphing)? | Yes |
| Cracking (Shooting cracks)? | Yes |
Observation: Hatcher Pass
Location: Eldorado Test Slopes
IMB parking lot to Eldorado test slopes to north ridge of Skyscraper.
Obvious signs of instability
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
Broken skies trending towards Obscured
Calm
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.
Snowpack
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.
Eldorado Test Slopes-15-Dec
Eldorado shouder-15-Dec
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