Avalanche Forecast
Issued: Jan 22nd, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Wind Slabs.
zryan,
Avalanche Canada
Take a big step back from wind-loaded terrain as active wind-loading will add load to a shallow, weak, and volatile snowpack. Consider the slopes above and adjacent to you as remote trigging is a very real concern.
Summary
Confidence
Moderate
Avalanche Summary
No new avalanches were reported in the past few days in the region but observations are limited.
We expect that fresh, reactive wind slabs will build overnight and throughout the day on Monday. These slabs may be reactive to human triggering and have a very real potential to step-down to deeper instabilities with a weak and shallow snowpack below.
Large natural and human-triggered persistent slab avalanches will be possible with active wind-loaded and several layers of concern in the mid and lower snowpack.
If you are out in the backcountry please consider filling out a Mountain Information Network report.
Snowpack Summary
New snow continues to gradually accumulate. Strong westerly winds will continue to affect wind-exposed terrain and build fresh wind slabs in lee areas. On steep solar aspects, and sun crust may exist and at lower elevations, a rain crust exists.
Snowpack depths are shallower than normal, and several buried weak layers have been a concern over the past few weeks. One is a recently buried surface hoar layer found 30 to 60cm deep in sheltered terrain features at treeline and above. At this same depth, a crust exists on steep south-facing slopes. Another layer of facets, crust, and surface hoar was buried around Christmas and is now 50 to 90cm deep. Finally, a layer of large, weak facets buried in November is found near the bottom of the snowpack. This layer is likely most problematic in alpine terrain, where shallower avalanches could scrub down to these basal facets.
Weather Summary
Sunday night
Mainly cloudy with flurries, trace to 5 cm of accumulation. Alpine temperatures around -8 C. Ridge wind west 60-100 km/h. Freezing level drops to valley bottom.
Monday
Cloudy with flurries, less than 5 cm of accumulation. Alpine temperatures reach a high of -5 C. Ridge wind west 50-90 km/h. Freezing level rises to 1000 m.
Tuesday
A mix of sun and cloud. Alpine temperatures reach a high of -5 C. Ridge wind northwest 40-60 km/h. Freezing level rises to 1100 m.
Wednesday
Partially cloudy with isolated flurries. Alpine temperatures rise to -2 C. Ridge wind northwest 45-60 km/h. Freezing level rises to 1500 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
- Avoid all avalanche terrain during periods of strong wind.
Problems
Persistent Slabs
The snowpack is generally weak, shallow, and faceted. Several buried weak layers remain a concern in the mid and lower snowpack. At treeline elevations, the main concern is surface hoar and crust layers in the middle of the snowpack, especially on steep convex openings. In the alpine, the main concern is weak facets at the bottom of the snowpack, especially on rocky slopes with variable snow depths.
These layers could become more sensitive to rider triggering as active wind-loading adds load to this weak snowpack.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Wind Slabs
Strong to extreme westerly winds will redistribute the surface snow, stripping windward areas and creating deep deposits of wind slab in lee terrain features. Due to the strength of these winds, wind slabs may be found in more atypical locations such as at lower elevations, low down in start zones or pressed into broad gully features.
Be extremely cautious around wind-loaded areas, as wind slabs may be reactive to rider triggering and have the very real potential of stepping down to deeper instabilities creating large and consequential avalanches.
Aspects: North, North East, East, South East, South, North West.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 23rd, 2023 4:00PM
