Numerous large rider triggered avalanches continue to be reported in this region.
Triggering is most likely at treeline and above on wind-loaded slopes.
Several persistent weak layers exist in the upper metre of the snowpack. Small avalanches in motion may trigger these deeper layers creating very large and destructive avalanches.
Up to 60 cm of recent snow has formed reactive storm slabs. These slabs will be most reactive on wind-loaded slopes and on sunny slopes during periods of strong solar radiation.
Four large (size 2) and two small (size 1) natural slab avalanches, and numerous small human-triggered slab avalanches were reported in the alpine and treeline elevations on Tuesday. On Monday, numerous skier-triggered storm slab avalanches up to size 2 were reported primarily at treeline and above on a variety of aspects. Here's one example.
40 to 65 cm of recent snow and southwest winds formed slabs reactive to human triggers.
Concern remains for triggering persistent slab avalanches. These layers include:
Facets/surface hoar/crust from early March buried 40-70 cm.
Facets/surface hoar/crust from mid-February buried 60-100 cm
Facets/surface hoar/crust from late January buried 100-160 cm.
The lower snowpack is well settled and strong.
Wednesday night
Cloudy with 5 to 10 cm of snow. 30 to 50 km/h south ridgetop winds, treeline temperature -6 °C.
Thursday
Cloudy with 5 to 10 cm snow. 20 to 40 km/h southwest ridgetop winds. Treeline temperature -5 °C. Freezing level 1500 m.
Friday
Cloudy with 10 to 20 cm of snow. 40 to 60 km/h southwest ridgetop winds Treeline temperature -4 °C. freezing level 1500 m.
Saturday
Mix of sun and cloud. 20 to 40 km/h northwest winds. Treeline temperature -5 °C.
More details can be found in the Mountain Weather Forecast.
