Avalanche Forecast

Issued: Mar 2nd, 2023 4:00PM

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

Avalanche Canada cgarritty, Avalanche Canada

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Start small and gather information about the depth and slab properties of new snow as you move into the terrain. Expect more reactive avalanche conditions at higher elevations and in wind-exposed areas.

Summary

Confidence

Moderate

Avalanche Summary

No new avalanches were reported in the region on Wednesday, however several small skier cut and explosives triggered wind slabs were reported in adjacent regions. Two large naturally triggered deep persistent slabs were also observed in the Rockies south of Valemount.

Observations from the weekend storm, quite limited in this region, showed mainly small dry loose avalanches releasing naturally, especially on steep, sunny slopes, as well as with skier traffic. We expect some degree of a slab avalanche cycle also took place at higher, wind affected elevations over the weekend, particularly in areas like Pine Pass and the MacGregors, where up to about 40 cm of new snow accumulated with strong southwest winds.

Earlier last week there was evidence of deep persistent slab activity that occurred during a previous storm with avalanches up to size 3.5. While we currently expect the deep weak layer to be dormant in this region, riders should absolutely continue to avoid steep, thin, rocky slopes where triggering a deep persistent avalanche would be most likely, particularly near alpine ridgelines.

Looking forward, we expect a mix of gradually diminishing storm slab reactivity, a shift toward wind slabs being the most reactive slab problem, and continued dry loose hazard in sheltered areas where snow remains low density.

Snowpack Summary

Another round of stormy weather mid-week has so far brought about 15-30 cm of new snow to the region, with more to come overnight Thursday. For the most part the new snow adds to low density storm snow from the weekend (20-40 cm of it in the west of the region, closer to 5-15 in the east), but it may also have buried recent wind slabs in more exposed areas.

The recent variable storm totals overlie faceted (sugary), heavily wind affected snow from previous cold temperatures and north winds, now roughly 20-60 cm deep. This interface remains in question with storm slabs being generally slow to form over it over recent days.

The middle of the snowpack is generally strong.

A weak layer of large and weak facets is found near the base of the snowpack. The layer is currently considered dormant, except perhaps in very steep alpine terrain that is inherently shallow. Riders should continue to avoid thin, rocky terrain where the likelihood of triggering this layer is higher.

Weather Summary

Thursday night

Cloudy with continuing convective flurries bringing another trace to 10 cm of new snow. Moderate to strong southwest winds.

Friday

Cloudy with easing flurries bringing up to 5 cm of new snow and storm totals to 20-40 cm. Moderate southwest winds, easing over the day. Treeline high temperatures around -10.

Saturday

A mix of sun and cloud. Light to moderate east winds. Treeline high temperatures around -13.

Sunday

A mix of sun and cloud. Moderate to strong northeast winds. Treeline high temperatures around -15.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.
  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.

Problems

Storm Slabs

An icon showing Storm Slabs

Continuing snowfall is loading a pair of storm interfaces about 30 and 60 cm deep in higher snowfall parts of the region and up to about 30 cm deep where the storm wasn't as strong (east of the region). Although we expect surface instabilities to gradually become limited to wind-loaded areas, all steep terrain should be approached with serious caution over the near term.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Loose Dry

An icon showing Loose Dry

In higher snowfall parts of the region, increasingly deep accumulations of low density snow that hasn't formed into a slab may continue to produce large sluffs with rider traffic in steep areas.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Possible

Expected Size

1 - 1.5

Valid until: Mar 3rd, 2023 4:00PM