Professional Observation

Observation Details

Signs of Unstable Snow

We toured from the Tamarack parking area this morning and headed towards the Mammoth crest.

Skies were partly cloudy this morning, becoming overcast by the afternoon and temperatures remained near freezing. Strong winds this morning seemed to break by mid-day with moderate wind speeds along the crest. Ironically we observed the strongest winds of the day while we were at the cars both gearing up and after returning. Evidence of recent strong winds was abundant along our tour today with plenty of tree debris scattered around (pine needles, duff, and even one sizable tree that had recently been broken).

We observed some recent wind deposits along the groomed skate track that produced localized cracking under a hard stomp. Along the crest, we observed some significant cornice features in the Hollywood area as well as some decent cornice features on leeward terrain features below treeline. In this area we observed some evidence of recent cornice failures however none of these created subsequent wind slab avalanches. We conducted a couple of hand sheer tests in the deposition area at the top of hollywood chute and found 1F deposits ranging from 2′-18″ above 4 f snow below. Failures occurred under hard force and were non plainer in nature.   Only minimal amounts of snow transport were observed throughout the tour today and looking around the lakes basin it was quite remarkable how much more southerly aspects have been stripped of surface snow.

In sheltered terrain below treeline, we observed conditions to be pleasant and predictable. Significant settlement has been occurring in the snowpack since our last major storm. Settlement cones on trees would suggest settlement up to 2′ in places and movement is significantly easier than it was a few days ago. Our recent cold temperatures have also led to significant surface faceting which is helping keep surface snow soft and unconsolidated. We were able to test some steeper terrain BTL and found only minor sloughing of loose surface snow.  No signs of instability were observed along our tour today.

Snow Stability