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 20 or more cm of new snow being on the ground by Monday morning. The new snow is coming to rest on a variety of old surfaces including surface hoar and facets which could allow for surprisingly touchy storm slabs. Time for conservative terrain choices.
Summary
Confidence
Weather Forecast
There’s quite a bit of uncertainty surrounding Monday’s storm and there is a chance of the “Fernie Effect” kicking in which would enhance snowfall rates. The forecast really mellows out for the rest of the forecast period though.
SUNDAY NIGHT: Freezing level around 1500 m, moderate to strong southwest wind, 8 to 15 cm of snow.
MONDAY: Overcast at dawn with some clearing in the late afternoon, freezing level around 1400 m, light to moderate wind generally out of the southwest, 5 to 10 cm expected with potential for some enhanced convective snowfall throughout the day that could produce as much as 15 cm.
TUESDAY: Broken 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.
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 has been reported in the region since last Tuesday. Some storm slab avalanche activity is expected Sunday night into Monday.
Snowpack Summary
Sunday's storm snow is covering a variety of old surfaces including a firm crust on solar aspects, soft faceted snow and 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. Avalanche activity was last observed at the faceting interface between this crust and overlying snow on February 17.
The mid-pack is well settled and strong, but the base of the snowpack contains 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
Snowfall rates really picked up Sunday afternoon. We're expecting 8 to 15 cm Sunday night with southwest wind and another 5 to 15 cm Monday. New snow is sitting on a wide variety of old surfaces including facets and 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
