Avalanche Forecast

Issued: Feb 25th, 2020 4:00PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Storm Slabs.

Avalanche Canada ghelgeson, Avalanche Canada

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Careful with wind loaded features near ridge crest which may remain sensitive to human triggering. Watch those cornices too, the last storm added a bit of new growth to them and you can't trust a freshly formed cornice.

Summary

Confidence

Moderate - Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack.

Weather Forecast

The forecast is marked by a nice diurnal temperature swing with the freezing level rising to around 1500 m during the day and then returning to valley bottom at night which is all well and good. Things change Friday night when the freezing level is expected to go to 2500 m(ish) and stay there through Saturday evening. Get the cold snow while you can.

TUESDAY NIGHT: Freezing Level at valley bottom, light southwest wind at lower elevations, moderate to strong west wind at ridge top, no significant snowfall expected.

WEDNESDAY: Broken cloud cover, freezing level starting at valley bottom rising to about 1500 m, light southwest wind at lower elevations, moderate to strong west wind at ridge top, no precipitation expected.

THURSDAY: A few clouds in the AM, clear skies after lunch, freezing level starting at valley bottom rising to about 1800 m, light to moderate west/southwest wind at lower elevations, strong northwest wind at ridge top, no precipitation expected.

FRIDAY: Mostly clear skies, freezing level starting near valley bottom rising to about 2500 m, light to moderate west/southwest wind, no precipitation expected.

Avalanche Summary

Natural and human triggered wind and storm slabs to size 1.5 were observed Tuesday on north/northeast facing features above 1900 m. The human triggered avalanche ran on the early February crust.

Widespread natural and intentionally human triggered avalanche activity to size 2 was reported from all aspects Monday. One of the wind slabs was up to 45 cm deep in places. The bulk of the activity was above 1750 m which suggests that wind loaded features near ridge line appear to be the problematic features.

Snowpack Summary

Sunday's storm produced 15 to 25 cm of storm snow that has settled to about 18 cm of snow. This snow rests on a variety of old surfaces including a firm crust on solar aspects, soft faceted snow and old wind slabs near ridge crest. The new snow has been formed into variable wind slabs in exposed terrain features, especially those 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.
  • Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.

Problems

Storm Slabs

An icon showing Storm Slabs

15 to 25 cm of storm snow fell Sunday night into Monday. It seems to be most problematic in wind exposed features near ridge crest, a trend that is expected to continue into Wednesday.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Feb 26th, 2020 5:00PM