Avalanche Forecast

Issued: Mar 9th, 2021 4:00PM

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

Avalanche Canada mconlan, Avalanche Canada

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Buried weak layers remain possible to be triggered, where they still exist.

Summary

Confidence

Moderate - Uncertainty is due to how quickly the snowpack will recover and gain strength.

Weather Forecast

TUESDAY NIGHT: Clear skies, 20 km/h southwest wind, alpine temperature -8 C.

WEDNESDAY: Increasing clouds with late-afternoon snowfall, accumulation 1 to 3 cm, 20 km/h southwest wind, alpine temperature -6 C, freezing level 1500 m.

THURSDAY: Morning clouds then clearing, 20 km/h southwest wind, alpine temperature -6 C, freezing level rising to 1600 m.

FRIDAY: Clear skies, 20 km/h southwest wind, alpine temperature -4 C, freezing level rising to 1900 m.

Avalanche Summary

No avalanches were observed on the weekend or Monday, besides some small loose avalanche out of steep terrain. The most recent persistent slab avalanche activity was on Friday, being triggered by explosives.

Snowpack Summary

A few centimetres of snow overlies a thick melt-freeze crust in many areas, with the exception being on north aspects above around 1700 m. Wind slabs may still exist on northerly aspects at alpine and treeline elevations. On solar aspects and below the freezing level, the snow may moisten during the heat of the day.

Around 30 to 50 cm of snow overlies a variety of old interfaces that formed in mid-February. There hasn't been recent avalanche activity on this layer, but it remains possible to be triggered where it exists. The more active layer was buried late January, which is found 50 to 100 cm deep. This layer is mostly composed of sugary faceted grains, hard wind pressed snow, feathery surface hoar in wind-sheltered locations, and a melt-freeze crust on steep solar aspects. Periodic avalanches continue to be triggered on this. Check out this MIN for photos of the positioning of these layers in the snowpack.

Terrain and Travel

  • Be aware of the potential for large avalanches due to the presence of a persistent slab.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.
  • Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
  • When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.

Problems

Persistent Slabs

An icon showing Persistent Slabs

Two weak layers may exist between 30 and 100 cm deep. Widespread avalanche activity has already occurred on the layers, but they could still be triggered anywhere they haven't already failed. Look for signs of instability and continue treating the snowpack as suspect if you are uncertain whether the layer is still present in your riding area.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Mar 10th, 2021 4:00PM