Aspen
AvalancheDylan Craaybeek · Jan 31, 2023 · Aspen
Weather
Cold morning (-18C or 0F) with Broken cloud coverage and very light snowfall (S-1) at the trailhead at 7:00. Clouds cleared within an hour and Clear sky for the rest of the day seeing some cloud coverage far to the west around 15:00. Temperature remained cold throughout the day and intense shortwave radiation helped melt many sunny slopes and burn my nose.
Snowpack
Even in the shallow portion of the deep West Elks/Raggeds forecast zone the snowpack is uniformly deep on most slopes. The main concern throughout this area is the January 27 interface of near-surface facets (FCsf) and melt-freeze crust (MFcr)/ Facet (FC) combinations. The mid-November facet layer is buried too deep to affect on all slopes except for wind-scoured shoulders and repeat slopes and even on these slopes the Persistent Slab avalanche problem is Isolated and Unreactive. Even on the shallow slopes with a clear persistent weak layer of well-developed depth hoar (DH) present, it was 4F to 1F- hard and 10-20cm thick at the very bottom of the snowpack showing clear signs of rounding. Average height of snow (HS) on southerly and westerly slopes ranged from 160-220cm and on northerly and easterly aspect HS ranged from 250-320cm (well over 350cm on wind-loaded slopes). There is 40-70cm of 4F to F hard (on the hand hardness scale) snow at the top of the snowpack that was rapidly settling and becoming more reactive throughout the day. New snow was more reactive on southerly slopes getting some shooting cracks traveling up to 10 feet beyond ski tips but not sliding even on slopes around 40 degrees steep. Extended column tests showed non-propagating failures on the Jan. 27 interface. The bottom line is there are basically two persistent weak layers in the snowpack and only one is concerning, and most likely will only be concerning for a few more days to maybe a week or two at most. The mid-November persistent weak layer is out of play on almost all slopes in this forecast area. The current weak layer of concern is from the short dry spell prior to the most recent storm arriving on January 27. A two to three foot slab now rests on top of FCsf and MFcr/FC combos on almost all aspects and elevations. The only slopes that are not as concerning are low-elevation sunny slopes that settled to less than a foot thick and developed a MFcr throughout the day today.
Avalanche
Observed numerous D1 to D2 slab avalanches all on wind-loaded terrain features and all of them failing in the new snow and not stepping down into deeper buried weak layers.