Natural Avalanche and Thick Drifts at Buck Ridge

Natural Avalanche and Thick Drifts at Buck Ridge

Date
Activity
Snowmobiling

We rode through first and second Yellowmule at Buck Ridge. There was a natural avalanche below the cornice line on the headwall above second Yellowmule that broke within the last 12 hours as it was not covered by any new snow. From a distance, it looked to be ~200' wide and broke 1-3' deep. I believe it failed just under the storm snow, not of deeper weak layers, but a very large cornice, hang fire (snow that didn't avalanche above the crown), and ongoing loading from snow and wind made it unsafe to investigate more closely.

The storm total farther back in the area was 20" of thick snow. Strong winds were creating heavy drifts in many areas. Human-triggered avalanches are likely on steep slopes, especially those loaded by fresh drifts. We dug one pit near the entrance of 2nd Yellowmule, we saw the buried weak layers, but they did not react in our stability test... We tested the snowpack for scientific interest. We planned to, and did, stay off steep slopes and the runout zones of slide paths and recommend that folks do the same until the storm is over and the snow has a chance to stabilize. The lack of propagation is a good sign for longer term stability, and I expect slopes to stabilize relatively quickly once the storm is over and wind-loading lets up. 

Region
Northern Madison
Location (from list)
Buck Ridge
Observer Name
Dave Zinn