Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 3
The problem still exists. While warm temperatures are helping the snowpack, it is not an overnight healing process. Continued avalanche activity demonstrates that dangerous avalanche conditions still exist on any slope that had any snow before last week. Last week’s storm system left a 2-3 foot soft slab sitting on top of a foot of weak facets at the ground. These lingering facets can be found above 9500 feet facing W, NW, N, NE, E, and SE and on NW, N, NE and E aspects between 8000 and 9500 feet.
While the avalanche activity is becoming more sparse, the threat remains. Triggering an avalanche today is still likely, and it would be 2-3 feet deep (or deeper on wind loaded slopes) and hundreds of feet wide.
Winds have calmed down but southerly winds on Sunday and Monday drifted snow and provided additional loading on many of these slopes.
Today the best option is to avoid terrain steep enough to slide. Ride slopes less than 30 degrees, and avoid being under any steep slopes as you can still trigger slopes from below. View a simulation of how this happens HERE.
Photo (B. Torrey) below shows this simple layering of this avalanche problem - a soft slab of snow resting on this persistent weak layer.