Avalanche Forecast
Issued: Feb 19th, 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.
wlewis,
Avalanche Canada
Keep terrain selection conservative as storm snow accumulates.
Small avalanches may step down to deeper instabilities, most likely on sheltered north facing slopes.
Summary
Confidence
Weather Forecast
SATURDAY NIGHT: Light snowfall overnight, 5-10cm possible. Winds ease to light southwesterlies. Freezing levels drop below 1000 m.
SUNDAY: Mostly cloudy with flurries bringing 5-10 cm of snow and light winds from the northwest. Freezing levels drop to valley bottom. Alpine high of -5.
MONDAY: Mix of sun and cloud, light winds from the northeast. Freezing levels at valley bottom with alpine highs of -10. Chance of flurries.
TUESDAY: Mostly clear skies with moderate easterly winds. Freezing levels below valley bottom, with alpine highs of -20.
Avalanche Summary
While no significant human triggered avalanches have been reported over the past week, the incoming storm will likely form reactive storm slabs as snow accumulates.
We have seen limited recent avalanche activity on the late January surface hoar layer, with the most recent report being a cornice triggered size 2.5 slab west of Forster Creek last Sunday (Feb 13). This avalanche occurred on north aspect at 2250 m. There is uncertainty about whether this problem will become more reactive with the incoming storm.
Snowpack Summary
New snow will form storm slabs at all elevations. The storm snow will bury a small surface hoar layer in sheltered terrain - which sits over a melt freeze crust on solar aspects at all elevations, and wind effected surfaces in exposed terrain.
A layer of buried surface hoar sits 30-50cm deep in the upper snowpack, most likely to be found and triggered on north aspects in sheltered areas. This layer has produced variable results in recent snowpack tests, and may still be reactive on some steep convexities.
The lower snowpack is well consolidated, with a crust/facet layer found 80 to 150 cm deep. It is currently considered dormant, but could become active later this season. Check out the forecaster blog for more information.
Terrain and Travel
- Watch for fresh storm slabs building throughout the day.
- If triggered, storm slabs in-motion may step down to deeper layers and result in very large avalanches.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
Problems
Storm Slabs
Fresh and reactive storm slabs will build overnight and into Sunday. Expect deeper deposits in wind affected areas - around ridgelines and on easterly facing slopes.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Persistent slab avalanches are possible due to a surface hoar layer found 20 to 40 cm deep. While avalanche activity on this layer has been isolated lately, caution should be taken around steep open slopes at treeline, especially in terrain where surface hoar is most likely to be preserved - like cut blocks.
Aspects: North, North East, East, North West.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Valid until: Feb 20th, 2022 4:00PM
