Avalanche Forecast

Issued: Mar 10th, 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

Email

Buried weak layers remain possible to be triggered, where they still exist. Be cautious on sun-exposed slopes and around cornices during the heat of the day.

Summary

Confidence

High -

Weather Forecast

WEDNESDAY NIGHT: Cloudy with snowfall then clearing, accumulation 2 to 5 cm, 10 km/h southwest wind, alpine temperature -8 C.

THURSDAY: Clear skies, 20 km/h southwest wind, alpine temperature -5 C, freezing level rising to 1500 m.

FRIDAY: Clear skies, 10 km/h southwest wind, alpine temperature -2 C, freezing level rising to 1900 m.

SATURDAY: Clear skies, 10 km/h southwest wind, alpine temperature 2 C, freezing level 2600 m.

Avalanche Summary

A few small loose and slab avalanches were triggered on sun-exposed slopes in the alpine during the heat of the day on Wednesday.

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. Cornices may also weaken over 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 layer. Check out this MIN for a photo 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.
  • Cornices become weak with daytime heating or solar exposure.
  • Avoid exposure to steep, sun exposed slopes, especially when the solar radiation is strong.
  • Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
  • 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 11th, 2021 4:00PM