Avalanche Forecast
Issued: Jan 23rd, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Wind Slabs.
TRettie,
Avalanche Canada
Continue to make conservative decisions. As the freezing level rises persistent weak layers could become more sensitive to rider triggering.
Summary
Confidence
Weather Forecast
Sunday night: freezing levels falling to 600m around midnight. Light rain turning to snow with light to moderate southwest winds.
Monday: Partially cloudy. Freezing level rising to 2500m. Light southwest winds with no precipitation expected.
Tuesday: Mainly cloudy, light precipitation. Freezing level around 1000m. Light to moderate southwest winds.
Wednesday: some light precipitation with light winds. Freezing levels around 900m.
Avalanche Summary
On Saturday a size 1 skier remote was reported on a northeast aspect at 1200m. This avalanche failed while a group was skiing on a supported feature with steeper terrain adjacent to them. It failed on a surface hoar layer. This avalanche is a good indication of the sensitivity to triggering.
On Friday, operators north of Terrace reported several skier-remote wind slab avalanches size 1.5-2.5 that failed on a surface hoar layer.
On Thursday, numerous natural, human-triggered, and remote-triggered storm slab avalanches up to size 2.5 were observed throughout the region. A buried layer of surface hoar, and below 1300m a thick melt-freeze crust likely contributed to the reactivity and wide propagation of these storm slabs.
Snowpack Summary
Last week's storm brought up to 50cm of snow with warm temperatures, building a denser slab above a weak layer of buried surface hoar and a thin melt-freeze crust below 1300 m. The presence of these weak layers means reactivity might persist for longer than usual. In wind loaded areas, associated strong southwest winds have created wind slabs in lee areas.
A layer of sugary facetted grains may be found about 80 to 130 cm deep, which formed during the cold spell in late December to early January. To date, this layer has only been problematic in the northern half of the region.
The remainder of the snowpack is strong in the south of the region. In the north of the region, the base of the snowpack consists of faceted grains around a melt-freeze crust, which is currently dormant.
Terrain and Travel
- Be aware of the potential for large avalanches due to the presence of buried persistent weak layers.
- The more the snowpack warms-up and weakens, the more conservative you`ll want to be with your terrain selection.
- Be careful as you transition into wind affected terrain.
Problems
Persistent Slabs
Last week 30 to 50 cm of new snow fell with warm temperatures, creating a denser slab above a weak layer of surface hoar which sits on a hard melt-freeze crust below 1300m. Below ~1000m, rain on snow has probably destroyed this layer of surface hoar and formed a crust on the surface. The most suspect areas would be sheltered, open areas near treeline.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Wind Slabs
Overnight snowfall will add to this week's 30-50cm of new snow. Southwest winds will have continued to build wind slabs in lee areas in the alpine and treeline.
Aspects: North, North East, East, South East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 24th, 2022 4:00PM
