Avalanche Forecast
Issued: Feb 1st, 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
While refrozen surfaces at lower elevations pose little avalanche hazard, large avalanches may be triggered in areas with wind-drifted snow at higher elevations. Be prepared to assess conditions and adjust your travel as you gain elevation.
Summary
Confidence
Moderate - Uncertainty is due to how quickly the snowpack will recover and gain strength.
Weather Forecast
Saturday night: Cloudy, 5-10 cm of snow, moderate west winds, alpine temperatures dropping to -12 C.
Sunday: Increasing cloud, isolated convective flurries with trace accumulations, light southwest winds, alpine high temperatures around -8 C.
Monday: Mix of sun and cloud, isolated flurries with a trace of new snow, light west winds, alpine high temperatures around -10 C.
Tuesday: Increasing cloud, isolated flurries with trace accumulations, light southwest winds, alpine high temperature -10 C.Â
Avalanche Summary
During the storm, numerous large (size 2-2.5) storm slab avalanches were reported in the region. They released naturally as well as from human and explosive triggers. These avalanches occurred on all aspects, mainly at treeline and alpine elevations. Reports indicate that cornices may be reaching their breaking point and may act as triggers for these avalanches. Below tree line, small wet loose avalanches were releasing naturally on Saturday.
There were two notable natural avalanches reported in the Selkirks on Thursday. These were very large (size 3.5-4) persistent slab avalanches breaking 100-250 cm deep on both southeast and northwest slopes above 2400 m. These avalanches add to the previous two observations of very large persistent slab avalanches over the past week. Although the likelihood is decreasing in the aftermath of the storm, easier-to-trigger storm slab avalanches or cornice fall may have the potential to step-down to this layer in isolated areas.Â
Snowpack Summary
30-60 cm of storm snow has accumulated at upper elevations (generally above 1900 m). Higher snow totals fell in the northeastern parts of the region. Extreme southwest winds have drifted the snow into deeper, stiffer slabs in wind-exposed areas and have rapidly loaded cornices. During a warming event Saturday night, rain saturated snow surfaces up to around 1900 m that have since refrozen with cooling temperatures.
The mid and lower snowpack is generally well settled and strong. In the north of the region, a weak layer of surface hoar buried 90 to 170 cm deep may persist in isolated areas.
Terrain and Travel
- Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Remember that the snowpack will be significantly different at higher elevations than lower down.
- When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.
Problems
Wind Slabs
Extreme winds from the southwest have drifted the storm snow into stiff slabs in wind-exposed areas that may be prone to human-triggering. This wind slab problem overlaps with areas where cornices have been rapidly loaded and could also act as triggers.
Aspects: North, North East, East, South East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 2nd, 2020 5:00PM
