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
Avalanche Summary
On Tuesday, explosives control had several deep persistent slab results to size 3.5.
On Monday, A skier accidental avalanche was observed in the Sun Peaks backcountry. The avalanche was a size 2 and is suspected to have run on a weak layer of surface hoar from late January. Several natural storm slab and wind slab avalanches were reported, size 1-2.5, on east and north aspects at treeline and alpine.
On Sunday, several natural slab avalanches were observed in the region, size 1-2.5, on all aspects between 1600 m and 2400 m. A size 2 skier accidental storm slab avalanche was reported at upper treeline. The avalanche was 30 cm deep and fractured on an unsupported roll.
On Saturday, numerous natural storm slab avalanches were reported throughout the region to size 3. Storm slabs were particularly touchy between 1800 m and 2400 m on north and east aspects in lee areas. A skier accidental storm slab avalanche size 2.5 was reported on an east aspect at 2350 m.
Snowpack Summary
Flurries continue to build upon previous storm snow totals bringing 45-60 cm of new snow to the Monashees and 30-75 cm to the Selkirks and west Purcells. Southwesterly winds continue to transport storm snow into deep pockets in lees. This 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.
Below the recent snow is a crust that extends up to 1800 m in the northern part of the region and up to 2000 m further south. This crust is buried about 40 to 100 cm deep and may host small facets on the crust.
Deeper in the snowpack two layers of surface hoar which formed in early January are 60 to 120 cm deep. These weak layers are still on our radar, although snowpack tests are indicating they may be strengthening.
Large and weak facets from November are near the base of the snowpack, which continue to produce very large avalanches in the region, as described in the Avalanche Summary.
Weather Summary
Tuesday Night
Cloudy with flurries, 5-10 cm accumulation. The eastern and southern Selkirks and west Purcells will see locally higher amounts of 15 cm. Ridge wind west 40 km/h easing to light by morning. Alpine temperatures reach a low of -5 °C. Freezing levels drop to valley bottom.
Wednesday
Cloudy with sunny periods in the afternoon and isolated flurries, 1-5 cm accumulation. Ridge wind west 20 km/h. Alpine temperatures reach a high of -6 °C. Freezing level 1000 metres.
Thursday
Sunny with cloudy periods in the afternoon and isolated flurries, 2-5 cm accumulation. Southwesterly ridge wind 40-60 km/h. Alpine temperatures reach a high of -4 °C. Freezing level 1000 metres.
Friday
Cloudy with flurries, 5-10 cm accumulation. Westerley ridge wind 20-40 km/h. Alpine temperatures reach a high of -3 °C. Freezing level 1200 metres.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
- Avoid open slopes and convex rolls at and below treeline where weak layers may be preserved.
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
Problems
Storm Slabs
The snowpack is struggling to adjust to a heavy load of 30-70 cm of storm snow from this week's storm. In all exposed areas, new snow and strong southwesterly winds have built deep pockets in less that remain reactive to natural and human triggers. Watch for signs of instability such as shooting cracks and recent avalanches.
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. This layer continues to produce 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. 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 in our latest Forecasters' Blog.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Numerous problematic weak layers exist in the top meter of the snowpack. Recent observations suggest these layers are gaining strength, but we would continue to be cautious around steep openings within and near treeline elevations as active loading continues. These layers have been most prevalent in the southern part of the region.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 8th, 2023 4:00PM
