Avalanche Forecast
Issued: Mar 13th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
astclair,
Avalanche Canada
Strong winds are drifting snow into touchy slabs. Stick to sheltered terrain and avoid exposure to overhead hazards on Saturday.
Summary
Confidence
Weather Forecast
Friday night: Cloudy, 5-10 cm of snow, strong northeast winds, alpine temperature -28 C.
Saturday: Cloudy, 5-10 cm of snow, moderate northeast winds, alpine high temperature -23 C.
Sunday: Mix of sun and cloud, light northeast winds, alpine high temperature -14 C.
Monday: Mostly clear, light northeast winds, alpine high temperature -10 C, freezing level 1000 m.
Avalanche Summary
Strong easterly winds are forming touchy wind slabs at all elevations. Cornices have also grown large with the recent weather, and a cornice failure could trigger a wind slab avalanche on the slope below. On Friday, there were reports of cornice falls triggering small wind slab avalanches.
Over the past few days, there have been several reports of natural, human-triggered, and explosive-triggered avalanches releasing in the previous storm snow, primarily on lee aspects above 1900 m. These avalanches were small to large (size 1.5-2), breaking 20-60 cm deep, and in a few cases, triggered by cornice falls.
Snowpack Summary
Snowfall amounts are expected to be highly variable. Anywhere from 5-20 cm may accumulate by Saturday afternoon. Strong easterly winds are drifting the recent snow into touchy wind slabs, and there is ample snow for transport with this reverse-loading pattern. These conditions may also bring cornices to their breaking point.
A total of 30 to 60 cm of snow from the previous storm has been redistributed by wind or is well-settled. This snow sits over another layer of buried wind slabs in exposed areas and a sun crust on solar aspects (south through west facing slopes). Melt-freeze crusts extend up to 1900 m on other aspects.
A thick crust/facet layer currently sits 30-60 cm below the surface. There has been only one avalanche reported on this layer since February 17th. The middle of the snowpack is generally strong, but the base of the snowpack contains weak basal facets that are most prominent in shallow rocky start zones.
Terrain and Travel
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Avoid exposure to slopes that have cornices overhead.
- Stay off recently wind loaded slopes until they have had a chance to stabilize.
Problems
Wind Slabs
Strong easterly winds are transporting recent snow onto lee features and building touchy wind slabs. There is ample snow for transport with this reverse-loading pattern, and another 5-10 cm of snow is possible by Saturday afternoon (up to 20 cm of snow may fall in favored up-slope areas). These conditions may also bring cornices to their breaking point.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 14th, 2020 5:00PM
