Buried surface hoar and a strong Dec 1 layer on Tamarack Peak

We dug a pit today at the site of the Dec 4 persistent slab avalanche to compare the current state of the Dec 1 layer to when it was last assessed in this avalanche path on Dec 8. Probing snow depth as we moved across the slope, HS abruptly decreased from 170 cm to 100 cm as we crossed over the well covered but still discernable climber's left flank and onto the bed surface of the Dec 4 avalanche.

Snowpit data collected today from the old bed surface in the start zone showed substantial strength gains in the Dec 1 layer and no indications of any lingering reactivity. At this location, the Dec 1 layer sat in a shallow snowpack state on the exposed bed surface from the time of the Dec 4 avalanche until the next storm cycle began on Dec 10. This period was characterized by calm weather and cold air temperatures which would have been conducive to addtional faceting. Since the Dec 10-12 snowfall, this site has remained more shallow than the adjacent portions of the slope that did not avalanche. If any lingering potential weakness existed in this layer, this site should have highlighted it.

Touring around the other portions of Tamarack Peak we noted small surface hoar of 2 to 6 mm buried under a very thin wind crust that existed on the snow surface in most open areas on N-NE-E. We observed this buried SH up to at least 9,600'.

The snow surface remained cold and unaffected by melt in nearly all areas that we traveled. The one exception we encountered was on a SE aspect at about 9,000' where the top 10 cm of the snowpack was undergoing melt-freeze.