Avalanche Forecast
Issued: Feb 25th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
jleblanc,
Avalanche Canada
If you see any blowing snow, seek out sheltered terrain where the snow will not be wind affected and riding will be at its best.
Summary
Confidence
Moderate - Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack.
Weather Forecast
The ridge of high pressure will keep the region dry and cold, with the potential for lingering valley clouds. The next round of snow is expected late Saturday night as a shift in the weather pattern will occur.
Friday night: Clear periods. Lingering valley cloud. Alpine temperatures around -15 C. Light westerly winds.
Saturday: Cloudy with isolated flurries. Freezing level rising to 1000 m. Alpine temperatures around -8C. Strong southerly winds.
Sunday: Snow 5-10 cm. Freezing level rising to 1400 m. Alpine temperatures around -6 C. Strong southerly winds up to 60 km/h.
Monday: Snow 10-15 cm. Freezing level rising to 1600 m. Alpine temperatures around -2 C. Strong southerly winds up to 60 km/h.
Avalanche Summary
No new avalanches were reported nor observed in the last 24 hours. If you venture out in the mountains, please consider completing a Mountain Information Report to share riding conditions or photos.
Earlier this week, shifting arctic winds have redistributed the storm snow into wind slabs and several natural avalanches occurred. Evidence of a widespread natural avalanche cycle from the last weekend’s storm is still visible.
As the last storm added load to the snowpack, the mid-January weak layer began to "wake up". In the neighboring region of North Colombia, large cornice-triggered natural persistent slab avalanches on an east aspect at treeline were reported earlier this week.
Snowpack Summary
Recent cold temperatures and northerly winds have modified and transported the last storm snow (20-80 cm), creating heavily wind-affected surfaces in exposed areas and wind slabs in lee areas. Below ~1200 m, 10-20 cm of snow is now overlying a thick melt-freeze crust.Â
Up to 120 cm now overlies a weak layer formed in mid-February. This layer is comprised of surface hoar in sheltered areas, a melt-freeze crust at lower elevations, a sun-crust on steep solar aspects, and hard wind-affected snow in the alpine and exposed treeline. Reports suggest that in many areas, the recent snow is bonding poorly to this firm layer.
The late-January surface hoar/crust layer is now down 50-150 cm in the snowpack. During the last week, there was reactivity on this layer in the neighbouring Colombia regions. This layer may also be a concern in the Cariboos with a similar upper snowpack composition.
Terrain and Travel
- Pay attention to the wind, once it starts to blow fresh sensitive wind slabs are likely to form.
- Recent wind has varied in direction so watch for wind slabs on all aspects.
- Closely monitor how the new snow is bonding to the old surface.
- Shooting cracks, whumphs and recent avalanches are strong indicators of an unstable snowpack.
Problems
Wind Slabs
Strong upcoming winds will have the potential to reload previously scoured slopes and build reactive wind slabs on immediate lee features of north-facing alpine slopes. Uncertainty remains about how much low-density snow will get transported and how well the developing slabs will bond to old surfaces.
Older and stiffer wind slabs still exist on various aspects in any exposed terrain and around ridgelines, as the past winds blew from various directions, creating slabs in less common locations.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
There are two prominent weak layers in the upper meter of the snowpack.
An upper layer exists down ~50-100 cm and is comprised of surface hoar in sheltered areas, a crust at lower elevations and on solar aspects, and hard wind-affected snow in the alpine and exposed treeline. Be particularly cautious in sheltered areas where surface hoar may be preserved, or south-facing aspects where recent wind-loading has occurred and a sun crust may be buried.
The lower layer may be found 100-150 cm deep in the snowpack. This layer consists of faceted snow, a sun crust on steep solar aspect, and most notably large surface hoar crystals in sheltered terrain. The last storm caused this layer to 'wake up' on northerly aspects around treeline in the neighboring regions. The most reactivity on this layer has been seen between 1600-2200 m in open areas in the trees, in cut blocks, and on steep convexities. Terrain features to be suspect of include the lee side of ridges, openings in trees, cut blocks, and burns, especially on northerly aspects where the layer may not be capped by a firm crust.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 26th, 2022 4:00PM
