No obvious signs from today, but we did see debris from several avalanches that occurred during the last storm (Dec.15-18)on the SW aspect of Tenderfoot and the SW face of Butch. Both starting zones were just below the ridgeline.
Observation: Summit
Location: Tenderfoot
Standard route of up W aspect to 2900′
Observer Comments
Weather
-4F at 1200'
19F at 2900'
Winds were light from the E
No precip
Snow surface
Surface hoar (2cm at lower elevations and >1cm in the alpine on top of 4-6" of settle snow from Dec.15-18th storm
Snowpack
In general the snowpack is very thin, and is composed mostly faceted snow. The current structure is very poor and ripe for increasing avalanche danger with the arrival of new snow.
In the lower elevations (below 2500') the snowpack was between 10"-15" deep, getting deeper with elevation. This was very loose faceted snow where you feel the ground when skiing. There were two thin crusts, an old one that is decomposing near the ground with depth hoar below it. See photo. There was a second very light crust at the interface between last weekends snow (top 5") and the Fist hard facets below. This light crust was also found at 2900' just below the Dec.15-18 snow from last week.
In the upper elevations where the snowpack has been more wind affected, snow depths varied depending on aspect. Along the wind-scoured West ridge there was 3" of faceting old crust and on the Southern leeward aspect there was 2-3' snow composed of different densities of faceting snow. There was 8" of deteriorating m/f crust at the ground. Test results in a pit at 2900' on a SSW aspect showed propagation potential 12" below the surface, where an old wind slab failed on Fist hard facets. This pit was adjacent to the crown of an avalanche that occurred last weekend. There was also failure under the light crust in the upper 5" of the snowpack. See photos below.
Very loose faceted snow, very representative of the snowpack below 2500'
A jumble of different of faceted snow layers and crusts
The most concerning layer was this very loose faceted snow sitting under an old wind slab.
Two layers propagated within the top 12" of the snowpack at 2900' on a Southern aspect
Pit location at 2900' was adjacent to this old filled in crown that avalanched last weekend mid-storm
Surface hoar growth in the lower elevations was very large 2cm in places
Very thin snow coverage in the lower meadows
Natural point releases on E aspect of Seattle Ridge in Turnagain Pass, seen on the drive to Summit.
Looking up the last few hundred feet of the scoured W ridge of Tenderfoot