Aspen
AvalancheMike Floyd · Mar 27, 2021 · Aspen
Weather
Scattered clouds with occasional light flurries, decreased as the day went on to mostly sunny. The clouds and light wind kept snow surfaces fairly cool.
Snowpack
Variable snow depth as we transition to spring with moments of 0 to 50 to 150 cm of snow across short distances but most places worth traveling hold less than 120 cm. I traveled on north through east aspects below treeline to an observed natural avalanche from last week (March 20). The snowpack was supportive to skis, but boots went straight to the ground everywhere I traveled. On exposed, sunny aspects, the recent 15 cm of new snow was wet but reasonably well bonded to the snow beneath. In shaded areas, the snow remained cool. The reported avalanche was a persistent slab avalanche with a crown one to three feet deep. It may have started as a wet avalanche (as observers reported) as there are shallow and exposed rocks throughout the starting zone before stepping into deeper layers. See pics and profile for details. Overall, the snowpack is shallow and weak and should still be given respect. Places with supportive but overall shallow snow are most suspect (still). I think 4 feet of snow or less is still a good rule of thumb for where you are more likely to affect the weak layers below. I found great skiing in shady, lower-angle trees. Other than the old avalanche, I did not observe any signs of instability. Warming was not quite there for loose wet avalanches but could easily have been with a bit more sun.
Avalanche
This was a persistent slab avalanche HS-N-R2-D2 and estimated from March 20. Initial observers couldn't see the full slide. The start zone is 37 degrees. The crown was near shallow or exposed rocks, 1-3 feet deep, taking most of the snow in the start zone to the ground. The southeast-facing (skier's left) half of the chute did not slide from the top.