Avalanche Forecast
Issued: Feb 7th, 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
Moderate
Avalanche Summary
The poor visibility over the last few days has kept operators from seeing into higher elevations however several small natural wind slab avalanches were observed, up to size 1.5, at treeline on steep east-facing slopes.
On Saturday, wind slabs 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.
Snowpack Summary
An additional 10-15 cm of new snow, +20 in the Mcbride area, brings this week's storm snow totals to 60-100 cm. 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
Tuesday Night
Cloudy with flurries, 5-10 cm accumulation. Ridge wind southwest becoming west 20-40 km/h. Alpine temperatures reach a high of -7 °C. Freezing level drop to valley bottom overnight.
Wednesday
Cloudy with flurries tapering off in the morning, 1-5 cm accumulation. Periods of sun in the afternoon. Alpine temperatures rise to -7 C. 40 km/h west ridge wind west easing to light in the afternoon. Freezing level rises to 1000 meters.
Thursday
Partly cloudy with isolated flurries, 1-5 cm accumulation. Moderate ridge wind from the southwest picks up to 40-70 km/h in the evening. Alpine temperatures rise to -3 C. Freezing level rises to 1500 meters.
Friday
Cloudy with isolated flurries, 5-10 cm accumulation. Ridge wind southwest 20-40 km/h. Alpine temperatures rise to -2 C. Freezing level rises to 1300 meters.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- 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.
- Sheltered low elevation terrain will likely offer the best and safest riding today.
- 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. Carefully monitor the bond between new snow and old surfaces. 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 8th, 2023 4:00PM
