Avalanche Forecast

Issued: Feb 2nd, 2020 4:00PM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is moderate. Known problems include Wind Slabs.

Avalanche Canada cgarritty, Avalanche Canada

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Analyze the surface for wind loading patterns to navigate your way around our wind slab problem. One more day of this strategy before more new snow and another bout of extreme wind move into the region.

Summary

Confidence

Moderate -

Weather Forecast

Sunday night: Clear. Light northwest winds.

Monday: Becoming cloudy over the day with flurries beginning in the evening. Light variable winds, shifting southwest in the afternoon and becoming strong overnight. Alpine high temperatures around -11.

Tuesday: Cloudy with continuing flurries bringing 5-10 cm of new snow, 10-20 cm with overnight accumulations. Flurries increasing overnight. Moderate to strong southwest winds easing over the day. Alpine high temperatures around -3.

Wednesday: Cloudy winth easing flurries bringing up to 5 cm of new snow, 10-25 cm with overnight accumulations. Light southwest winds. Alpine high temperatures around -4 with freezing levels to 1000 metres.

Avalanche Summary

Observations were limited by weather on Saturday, but we have preliminary reports of the recent storm and associated natural avalanche cycle producing storm slabs to size 2.5. (large) in the Terrace area. 

So far, avalanche activity appears to have been limited to storm snow and not to have involved any deeply buried layers. With that said, a few crown fractures were noted at up to a metre in depth. Ski cutting of small features on Saturday produced small releases up to 30 cm deep.

Looking forward, our existing wind slab problem won't have much time to stabilize before yet another storm brings modest new snow amounts along with extreme winds to elevate avalanche danger again on Tuesday.

Snowpack Summary

60-80 cm of recent storm snow has been heavily impacted by strong winds from varying directions, forming reactive wind slabs on all aspects in wind-exposed areas. This snow overlies old wind affected surfaces in exposed treeline and alpine areas. 

90-150 cm of snow from the second half of January over lies a thin layer of facets that formed during the mid-January cold snap. Recent avalanche activity in the Bear Pass area and snowpack tests results have indicated that this layer remains a concern (check out this MIN report).

A crust from mid November exists at the base of the snowpack. So far, we have only one observation from Saturday in the far north of the region showing this layer waking up during the storm. Previously, the last avalanche reported on this layer was on January 17. Limited potential still exists for large avalanches in surface layers to step down to this layer.

Terrain and Travel

  • Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.
  • Be alert to conditions that change with elevation, aspect and exposure to wind.

Problems

Wind Slabs

An icon showing Wind Slabs

Deep accumulations of new snow have seen extensive wind redistribution as a result of strong winds from varying directions (most recently from the northwest). Expect to find increasingly deep and reactive new wind slabs as you gain elevation. Keep your guard up around steep slopes in sheltered areas where a stubborn storm slab may still react to a human trigger.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Valid until: Feb 3rd, 2020 5:00PM

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