New snow and wind will form sensitive storm slabs that may step down to weak layers within the complex upper snowpack.
Careful snowpack evaluation and conservative decision-making is key.
Weak layers in the upper snowpack of surface hoar/crust/facets continues to be loaded by new snow. Avalanche activity has tapered on the deepest weak layer recently but the snowpack structure remains a concern as new snow load is added.
Stormy conditions will bring 10 to 20 cm of new snow to the region. The new snow adds to snow that recently buried a layer of surface hoar. Storm slab avalanches could step down to deeper weak layers described in the snowpack summary
On Saturday, several small size 1 to 1.5 storm slab avalanches and numerous dry loose were reported. Storm slabs were releasing down to the most recent surface hoar layer.
Several Mountain Information Network posts describe human-triggered slab avalanches failing on crusts and/or surface hoar layers down roughly 30 cm.
Looking forward, weak layers described in the snowpack summary are likely to remain sensitive to human-triggers as they are loaded with new snow.
New snow and moderate to strong wind further buries weak layers in the upper snowpack. This region is highly variable with similar weak layers that vary widely in depth and distribution:
On February 13th a surface hoar layer and/or a crust on solar aspects was buried, it is down 10 to 20 cm.
On February 7th a surface hoar layer/crust layer (depending on aspect) was buried. Snow above this layer is settling and it is down 15 to 30 cm. Greater depths in wind loaded areas.
On January 26th, a surface hoar/crust layer sitting on a facet layer was buried and is down 50 to 70 cm.
This weak snowpack structure will continue to produce avalanches as new snow loads it.
The mid and lower snowpack remain well settled.
Sunday Night
Mostly cloudy. 1 cm of snow. 30 km/h southwest ridgetop wind. Treeline temperature -8 °C.
Monday
Cloudy. 10 to 20 cm of snow. 30 km/h south ridgetop wind. Treeline temperature -5 °C.
Tuesday
Mostly cloudy. 4 to 5 cm of snow. 20 km/h south ridgetop wind. Treeline temperature -7 °C.
Wednesday
Mix of sun and clouds. 2 to 4 cm of snow. 10 km/h south ridgetop wind. Treeline temperature -9 °C.
More details can be found in the Mountain Weather Forecast.
