Avalanche Forecast
Issued: Mar 11th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
JSmith,
Avalanche Canada
10-20 cm of forecast snow and moderate west winds on Friday night will form fresh storm slabs that will be most reactive in wind affected terrain.
Start in simple terrain and use small slopes with low consequence to test the bond of the new snow.
Summary
Confidence
Weather Forecast
FRIDAY NIGHT: Snow; 10-20 cm / Moderate west winds / Low of -6 / Freezing level 700 m.
SATURDAY: Flurries; 5-10 cm / Light southwest wind / High of 0 / Freezing level 1500 m.
SUNDAY: Mostly cloudy / Light southwest wind / High of 1 / Freezing level 1600 m.
MONDAY: Flurries; 5-10 cm / Moderate southwest wind / High of 1 / Freezing level 1600 m.
Avalanche Summary
Several natural and skier triggered wind slabs to size 2 were reported on Thursday. Additionally, a cornice failure triggered a size 2.5 slab avalanche.
Several very large human triggered persistent slab avalanches up to size 3 were reported last weekend. They occurred primarily in the Valhalla, Goat, and Kokanee Ranges typically on north through southeast facing slopes at treeline elevations. They were failing on a layer of surface hoar down 70-120 cm.
- Multiple size 2-3 avalanches were remotely triggered from ridgeline features up to 90cm deep.
- A snowmobile triggered size 2 occurred near Slocan. Read the MIN report here for full details.
The most likely triggers of these persistent slabs are large triggers such as smaller avalanches in motion, cornices, or snowmobiles.
Snowpack Summary
10-20 cm of forecast snow and moderate west winds on Friday night will form fresh storm slabs that will be most reactive in wind affected terrain.
The new snow will be sitting on a variety of surfaces including hard wind affected snow, sun crusts on southerly slopes, and surface hoar on shady or sheltered slopes. Expect storm slabs to be most reactive where they are sitting on either a sun crust or surface hoar.
The late February persistent weak layer combination of crust, facets and surface hoar is down 40-50 cm. Reports suggest this layer is becoming less reactive in most areas.
Two additional persistent weak layers from late January and mid-February are down 80-120 cm. They both consist of surface hoar and/or melt-freeze crusts. Recent trends indicate these layers have only been reactive in southern Selkirks around the Valhalla, Kokanee, and Goat Ranges. Several natural and human triggered avalanches occurred on these layers last weekend.
Terrain and Travel
- Be especially cautious as you transition into wind affected terrain.
- Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
- Minimize your exposure time below cornices.
Problems
Storm Slabs
10-20 cm of forecast snow and moderate west winds on Friday night will form fresh storm slabs that will be most reactive in wind affected terrain.
Cornices are very large in many areas. Cornice failures may trigger large avalanches on the slopes below.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Persistent weak layers of surface hoar and/or crust can be found 40 to 120 cm deep.
The problem is most likely found in the southern part of the Selkirks (e.g. Valhalla, Goat and Kokanee ranges), especially on open convex slopes at treeline elevations.
This problem exists on all aspects, however increased reactivity has been noted on northeast through southeast facing slopes.
Aspects: All aspects.
Elevations: Treeline.
Likelihood
Expected Size
Valid until: Mar 12th, 2022 4:00PM
