Thin snow coverage and poor structure in the Virginia lakes area

SNOWPACK OBSERVATION
North side of South peak
Submission Info
Monday, December 14, 2020 - 12:30pm
Red Flags: 
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain
38° 2' 30.5592" N, 119° 15' 7.3548" W
Snowpit Observations
More detailed information about the snowpack: 

I ventured out for a tour today in the Virginia lake area to get a look around and get an idea of the coverage after our most recent storm. While it was a welcome sight to see the mountains covered in a fresh blanket of white my investigations today found the snow to be pretty shallow and unsupportive. I think it will take another good storm to improve coverage in the bc and add a more supportive base to the snowpack.

I found new snow totals averaging around 20-30cm at mid elevations in areas that were sheltered from the wind. Overall coverage was variable with extensive bare patches in windward areas and sporadic wind deposits up to 2 meters thick, sometimes these two extremes are present within only a few feet of each other. Most of the terrain I traveled through today consisted of the new snow resting on bare ground. Although in some gully features and catchment zones I did find areas where the new snow is resting on old snow of varying thickness. (~40-60 cm total height of snow~) In these areas the structure is quite poor with the old snow consisting largely of well-developed fist hard facets 1-3mm in size. In some areas there was also a notable melt freeze crust between the older faceted snow and the newer surface snow. I dug in 3 locations today and found similar structure in the two locations with old snow present. (see profile for more information.) In my Investigations today I did not find this week interface to be reactive yet although, I suspect this is largely due to the low-density nature of the new snow. As we see this new snow consolidate into more of a slab I suspect the scales may tip. On that note, I also found quite a few micro terrain features with fresh wind deposits that were sensitive to my weight. Numerous shooting cracks were observed in wind loaded areas and I was also able to easily kick loose small pockets of wind slab from 10-40 cm thick. I would be extremely cautious in areas where the wind has deposited a more substantial load and that fresh slab is sitting on top of this weak faceted base.

 

We seem to be in a situation with two major hazards that are playing off of each other.

First, we have a VERY thin snowpack with many sharks lurking just below or, even poking through the surface. Walking around today I found ski pen to be basically on the ground level for most of my travels. Which brings me to the second issue.

The areas within the terrain with more substantial snow coverage (gullies, leeward slops, and mid-slope catchment zones) are likely to be the same place with more residual snow cover from the Mid November storms, thus the very poor structure and more potential for avalanche activity.

Snowpit or crown profile photo or graph: 
Snowpack photos: 
Snowpit videos (tests, etc): 
Weather Observations
Cloud Cover: 
50% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Light
Precipitation: 
None
Air temperature trend: 
Warming
Wind Direction: 
Southwest
Accumulation rate: 
None
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