Reactive Storm Slab on Hidden Peak

Location Name: 
Hidden Peak
Region: 
West Shore Area
Observation Date & Time: 
Saturday, December 26, 2020 - 13:00
Location: 
38.978649, -120.118262
Is this an Avalanche Observation?: 
No


Conditions Alerts:



Observation made by: Public

Tabs

Observation
Description of Snow, Weather, and Avalanche Conditions: 

First 500ft had limited coverage and required some creative navigation around and over downed trees. Snow continued to fall throughout the tour until almost 2pm with periodic breaks in the clouds. Wind was gusting on the way up and signs of wind affected snow were visible on much of the terrain even within the dense trees far below treeline. Witnessed small cracks shooting from the skin track but only extending a few feet at most. 

We dug a pit on the NE aspect at 8300ft to see if the new storm snow had overloaded the Dec 11 persistent weak layer. We were surprised to find over 15 inches of new consolidated snow from the recent storm, which was much more than forcasted amount (likely due to the wind depositing snow on this slope). We were able to easily identify the weak sugary facet layer about 40 inches below the surface. We were not able to impact this deep weak layer, however we easily triggered a reaction on the interface of the old/new snow with a our test resulting in an ECT-21 @40cm (16in) depth and propagating across the full extended column (see images).

Skies cleared and wind subsided at the summit at around 2pm. We chose conservative low angle terrain on the way down and did not witness any other signs of instability. We had deep, dry, supportive snow for the first 1500ft. Below 7500ft things began getting thinner and more sharky, with the snow below 7000ft becoming very thin and tough to navigate.

Snowpit or crown profile photo or graph: 
BESbswy