Aspen

Avalanche

Brian Lazar Matt Huber · Dec 3, 2018 · Aspen

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Weather

Snowing S1 throughout the day with around 3-4 inches of accumulation from morning to 3pm at the trailhead. There was around twice this accumulation near the peak. Skies were obscured to overcast, cold temperatures, and light westerly wind. Made contact with skiers that were able to verify HN24 on previous day. This allowed for accurate assessment of weekend storm totals of around 50-60cm above 10,500 ft.

Snowpack

Snowpack is getting deep quickly above 10,500 ft. Avg HS around 175-190cm in Marble Bowl. Weekend storm totals are approximately 50-60cm. Recent storm snow (including late last week) is around 90cm. The 90cm of low-density storm snow is resting on a soft mid-pack slab (supportable on skis but not in boots) above an early-season Nov crust-facet combination. There was some cracking in the storm snow, including shooting cracks up to 10m ahead of ski tips. The crust is eroding and turning to mostly facets. This layer is quite reactive (ECTPV failing upon isolation) producing numerous collapses though no whumpfing sounds today. Below the crust is another soft slab, all resting on 1mm facets, which are showing the earliest signs of rounding.

Avalanche

Poor visibility made it difficult to determine the precise extent of the avalanche that was triggered on Sunday, 12.2.18. While this avalanche clearly started in the storm snow, it stepped down to around 3-4 ft deep at east on the skier's right flank, releasing large chunks of debris.The bed surface of this avalanche was covered by around a foot of new storm snow by 2pm. This avalanche was sizeable and pulled out smaller pockets (mostly in the storm snow) as the debris ran down slope. collectively, this was a SS-ASu-R2-D2.5-O. Crown depth reached up to 90-100cm deep. The release at the crust-facet layer stepped into basal facets in areas. There is significant hang-fire left in the path, and it will be east to trigger another avalanche in this terrain if not on the bed surface, which at this point is hard to see clearly. The crust-facet combo is worrisome and travel on slopes over 35 degrees is a dangerous proposition right now.