Avalanche Forecast
Issued: Feb 6th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs, Deep Persistent Slabs and Persistent Slabs.
lbaker,
Avalanche Canada
Continued snowfall and wind have created dangerous avalanche conditions, especially around wind-loaded slopes. Sheltered terrain will likely offer the best and safest riding.
Summary
Confidence
Avalanche Summary
On Sunday, poor visibility kept operators from seeing into higher elevations however a few small natural wind slab avalanches were observed, up to size 1.5, at treeline on steep east facing slopes.
On Saturday, a few small wind slab avalanches were reported to be reactive to skier traffic at treeline. A natural wind slab avalanche, size 2, was reported on an east aspect at 2100 m.
On Friday, numerous natural wind slabs were observed throughout the region (size 2-2.5). A few large natural deep persistent slabs were also observed in the alpine and treeline (size 2.5-4).
Last weekend, several very large (size 3 to 4) avalanches were triggered naturally on the basal facets. The avalanches were on all aspects and generally in alpine terrain between 1700 and 2900 m. See here for a video of a rider-triggered avalanche near Renshaw and another example here near Clearwater.
High-consequence avalanche activity is ongoing for the past week. Your best defence is to stay diligent in choosing low-consequence terrain away from overhead exposure.
See more on the potential of triggering deeper weak layers Forecasters' Blog.
Snowpack Summary
Flurries continue to build upon 60-90 cm of recent low-density storm snow that is settling quickly with warm temperatures. Southwesterly winds continue to transport storm snow into deep pockets in lees. Storm snow sits above a plethora of old snow surfaces including previously wind-affected snow at upper elevations, a sun crust on steep solar aspects, faceted snow, and surface hoar crystals in wind-sheltered terrain.
In the upper meter of the snowpack sits two layers of surface hoar crystals and/or a melt-freeze crust. The surface hoar is most likely found around treeline and lower alpine elevations. The melt-freeze crust is found up to 1800 m on all aspects and into the alpine on sun-exposed slopes.
Large and weak facets from November are near the base of the snowpack and continue to produce very large avalanches in the region.
Weather Summary
Monday Night
Mainly cloudy with isolated flurries, 5-10 cm accumulation, up to 15 cm in localized areas. Alpine temperatures reach a low of -4 °C. Ridge wind southwest 40-60 km/h. Freezing level 1400 metres.
Tuesday
Cloudy with flurries, 5-10 cm of accumulation. Alpine temperatures reach a high of -3 °C. Ridge wind southwest 20-40 km/h. Freezing level 1400 metres.
Overnight flurries bring 5-10 cm accumulation. Parts of the southern Cariboos may see localized higher amounts, up to 15-20 cm accumulation.
Wednesday
Mix of sun and cloud with isolated flurries, trace accumulation. Alpine temperatures rise to -7 C. Ridge wind west 20-40 km/h. Freezing level rises to 1000 meters.
Thursday
Partly cloudy with isolated flurries, 2-5 cm accumulation. Moderate ridge wind from the southwest picks up to 50-70 km/h in the evening. Alpine temperatures rise to -3 C. Freezing level rises to 1500 meters.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Watch for changing conditions today, storm slabs may become increasingly reactive.
- Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
- Minimize exposure during periods of heavy loading from new snow and wind.
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
Problems
Storm Slabs
Storm slabs continue to grow with additional snow and southwest winds. Slabs will likely be the deepest and most reactive on north and east aspects at treeline and above.
Keep in mind that storm slabs have the potential to step down to deeper weak layers, resulting in large and consequential avalanches.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
A layer of large and weak facets sits near the base of the snowpack. In the past week, this layer has produced very large avalanches that can travel far. Riders are most likely to trigger an avalanche on this layer in steep, shallow terrain, or by triggering a smaller avalanche that could step down to this layer.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Two surface hoar layers found in the upper 100 cm of the snowpack have been reactive in scattered areas around the region. Be especially cautious around steep openings within and near treeline elevations, especially where the recent storm snow has been wind affected.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 7th, 2023 4:00PM
