Observation: Cardiff Bowl

Observation Date
1/8/2021
Observer Name
Skidmore
Region
Salt Lake » Big Cottonwood Canyon » Cardiff Fork » Cardiff Bowl
Location Name or Route
Cardiff Bowl
Red Flags
Red Flags
Recent Avalanches
Cracking
Collapsing
Poor Snowpack Structure
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Same
Problem #1 Comments
A group of us dug a few dispersed pits along the way up to Cardiff Pass (pit elevation approximately 9,680ft). The pit I helped excavate was located on the side of a low knoll on a southeast aspect with an incline of 20 degrees. We found the upper layer of the snowpack to consist of a mixture of decomposing precipitation particles and graupel up to 25cm down. Between 25cm and 55cm showed rounded grains in addition to 4F trending to 1F hardness. From 55cm to the ground consists of 2mm facets with F+ hardness.
We got ECTN12 and ECTN 17 down 15cm and 21cm respectively; however, we did not initiate full propogation in the upper layers or any fracture at or below the 55cm layer with the ECT. We did get it to go on a CTH with a sudden collapse fracture down 60cm on the 2mm facets. We then did the propagation saw test and got PST 36/100 to the end of the column down 55cm on the 2mm facets. Another group digging a pit in the same area heard collapsing in the snowpack with shooting cracks visible on the surface as they approached their pit location.
Snow Profile
Aspect
Southeast
Elevation
9,600'
Comments
Very poor snowpack structure evidenced from pit profile and collapse within the snow pack. Additionally, the increased stiffness in the upper layers of the snowpack seem to be making the persistent weak layer approximately 2ft down more difficult to trigger with the ECT. Other tests show that layer is still very much in play, even on upper elevation southeastern aspects.
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Considerable