Snow/Wx Obs before the next storm comes

CB Avalanche Center 2018-19 Observations

Location: Paradise Divide Area
Date of Observation: 11/21/2018
Name: AR

Subject: Snow/Wx Obs before the next storm comes
Aspect: South West, West, North West
Elevation: 11,000′-12,800′


On a SW aspect of our descent, we had one small point release from the edge of a turn. New snow slid on the uppermost crust layer, but did not propagate and ran only about 50 feet. This point moved very slow, but did illustrate the potential for the newer deposited snow to slide on the crust below it, especially on aspects that have received solar radiation. As new snow accumulates with the forecasted Thanksgiving storms, this weak layering structure will become more reactive, with more fresh snow on the crust, and potentially on the lower crust or facets deeper in the snowpack.

Weather: Clear, calm weather. Steady mild temps throughout the day 26-30F, no clouds, no wind.
Snowpack: Our party of two toured on a western facing slope from 11,000′ to a ridge at 12,800′. The snow depth was variable depending on the terrain, ranging from 10-20 cms in the wind scoured upper chute to 80-90 cms in the open bowl below. We found a generally weak snowpack structure with little to no slab in most locations, though a prominent crust was present mid-pack shortly after we gained elevation from the valley floor. Digging two snow pits between 12,000 and 12,500 we found multiple crust layers mid-pack. The structure of the bottom of the snowpack was weak faceted snow, topped by 2-3 crust layers dependent on the aspect, topped by fresh and freshly wind deposited snow. SW or WSW aspects that had more solar exposure prior to last week’s storm cycle had a stronger crust. W and WNW aspects had a less defined crust. In shovel shear tests the weakest layer appeared to be between the crusts and popped fairly clean on a large facet layer between the crusts. Though we found and isolated the weakest layers, this layer did not propagate in ECTs, and with the variable structure due to terrain features, we found no slab or concern of propagation.
The surface of the snow was very soft for skiing, with few pockets of wind-stiffened snow.