Aspen

Avalanche

Brandon Levy, Dylan Craaybeek · Apr 6, 2023 · Aspen

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Weather

Clear skies with cold temperatures this morning (15F at the trailhead at 8:00) and warmed significantly by midday (35F at the trailhead by 12:00). Winds were calm with light snow transport visible along ridgelines.

Snowpack

A dust layer near or on the snow surface, a melt-freeze crust (MFcr) with large, well-developed facets on top of it around 50-80cm below the snow surface, and large depth hoar crystals making up the bottom 50cm of the snowpack spell trouble for backcountry travelers thinking there is a springtime snowpack this week into the weekend. Near and above the treeline the dust layer developed into a MFcr about 20cm below the snow surface while the dust made it to the snow surface below the treeline on most southerly and wind-scoured slopes. The MFcr of concern around half a meter deep near and above the treeline is around three to five cm thick with 1.5-3.0mm striated, faceted crystals on top of it. This is the layer of failure for an avalanche that was remotely triggered from about 200 feet away on a southeast-facing slope around 12,000ft. The basal depth hoar layer is also alive and well in this area making up the bottom 50cm or so of the snowpack and failing on extended column tests with hard taps or additional loading steps indicating it is probably unlikely to trigger with the weight of a human but an avalanche on upper persistent weak layers could step down if they gain mass and momentum on large, sustained slopes. East and southeast are the primary aspects of concern where both persistent weak layers are present with constant wind-loading forming cohesive slabs on top of them.

Avalanche

We observed several natural avalanches on north through southeast-facing slopes. Many of the natural avalanches resulted from cornice falls while others failed on slopes below cornices without evidence of any cornice failures. We remotely triggered a D2 (on the destructive scale) avalanche on a southeast-facing slope around 12,000 ft from around 200 feet away.