Avalanche Forecast
Issued: Feb 23rd, 2020 5:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs.
ghelgeson,
Avalanche Canada
This forecast is based on 5 to 10 cm Sunday night and another 5 to 10 Monday, but some valleys could see more. The new snow is coming to rest on a variety of potential weak layers that may allow for surprisingly touchy storm slabs. Time for conservative terrain choices.
Summary
Confidence
Weather Forecast
There’s quite a bit of uncertainty surrounding the precipitation associated with Monday’s highly variable storm. The forecast really mellows out for the rest of the forecast period though.
SUNDAY NIGHT: Freezing level around 1500 m, light to moderate west/northwest, 5 to 10 cm of snow.
MONDAY: Overcast at dawn with some clearing in the early evening, freezing level around 1000 m, light variable wind, 5 to 10 cm expected with potential for some enhanced convective snowfall producing as much as 20 cm throughout the day.
TUESDAY: Scattered cloud cover, freezing level starting at valley bottom rising to about 1500 m, light southwest wind at lower elevations, moderate to strong west/northwest wind at ridge top, no significant snowfall expected.
WEDNESDAY: Scattered cloud cover, freezing level starting at valley bottom rising to about 1500 m, light southwest wind at lower elevations, moderate to strong northwest wind at ridge top, no significant snowfall expected.
Avalanche Summary
No notable avalanche activity was reported in the region since Tuesday, some storm slab avalanche activity is expected Sunday Night into Monday
The most recent deep persistent slab activity we know about is described in this MIN report from February 11 and this MIN report on February 9th. This layer may become reactive again with a large trigger (like a cornice failure) or a sharp change in weather.
Snowpack Summary
Sunday/Monday's storm snow is covering a variety of old surfaces including a firm crust on solar aspects, soft faceted snow and possibly surface hoar in sheltered areas, and old wind slabs near ridge crest.
A thick rain crust sits 30-60 cm below the surface and can be found up to 2100 m.
A well consolidated and settled mid-pack overlies generally weak basal facets that are most prominent in shallow rocky start zones.
Terrain and Travel
- Don't be too cavalier with decision making, storm slabs may remain sensitive to human triggering.
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
Problems
Storm Slabs
We're expecting 5 to 10 cm Sunday night with southwest wind and another 5 to 10 cm Monday, but some areas could see as much as 20 cm. New snow is sitting on a wide variety of old surfaces including facets and possibly surface hoar which may allow for particularly touchy storm slabs on Monday.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 24th, 2020 5:00PM
