Stormy weather returns !
Avoid avalanche terrain during periods of heavy loading from new snow and wind.
Uncertainty is due to how buried persistent weak layers will react to the new load.
A weak layer from early March is now 120 to 175 cm deep with January and February layers buried 150 to 250 cm. There's still uncertainty about how the weak layers will react to the new load.
New snow and wind will create fresh and reactive slabs, especially on lee terrain features. Storm slabs in motion may step down to deeper layers resulting in large avalanches.
Persistent activity was reported Tuesday, with cornice fall triggering a large slab (size 2.5- 3) on an easterly alpine slope. A rider-triggered slab (size 2) was also triggered from steep, shallow, rocky southeasterly alpine slope. Both avalanches had crowns of 60 to 100 cm.
Small sluffs were triggered by riders on steep northerly slopes, producing loose dry avalanches on Monday.
Thanks for sharing your observations via the MIN if you are going out into the backcountry.
20 to 40 cm of new snow is expected by Thursday afternoon, forming touchy storm slabs. This overlies wind-affected snow in lee terrain at upper elevations and moist, heavy snow or a melt-freeze crust on southerly slopes, especially at lower elevations. This sits over 120 to 175 cm of settling storm snow from the past week.
Under it, a weak layer formed in early March that consists of a crust on all aspects except high north-facing slopes and facets or surface hoar in some areas. Weak layers formed in mid-February and late January are now buried 150 to 250 cm deep.
Below this, the snowpack is well-settled and strong.
Wednesday Night
Cloudy with 15 to 20 cm of new snow. 50 to 70 km/h south ridgetop wind. Treeline temperature -6 °C. Freezing level 800 m.
Thursday
Cloudy with 5 to 10 cm of new snow. 30 to 50 km/h south ridgetop wind. Treeline temperature -4 °C. Freezing level 1000 m.
Friday
Cloudy with 15 to 30 cm of new snow. 30 to 50 km/h southwest ridgetop wind. Treeline temperature -4 °C. Freezing level 1000 m.
Saturday
Cloudy with isolated flurries. 20 to 30 km/h northwest ridgetop wind. Treeline temperature -2 °C. Freezing level 1200 m.
More details can be found in the Mountain Weather Forecast.
