Avalanche Forecast

Issued: Mar 18th, 2021 4:00PM

The alpine rating is low, the treeline rating is low, and the below treeline rating is low. Known problems include Cornices.

Avalanche Canada swerner, Avalanche Canada

 

The region will see mostly cloud cover on Friday, but if the sun shines it could heat up fast. Pay attention to steep South facing slopes and back off if they heat up. Avoid exposure above or below cornices.

Summary

Confidence

High -

Weather Forecast

A Pacific frontal system reaching the Coast today will bring cloudy skies and snowfall to the Interior regions through the weekend.

Thursday Night: Snow 5 cm. Ridgetop wind strong from the southwest and alpine temperatures near -2. Freezing levels 1400 m.

Friday: Cloudy with sunny periods. Ridgetop wind strong from the southwest and freezing levels 1700 m.

Saturday: Mix of sun and cloud. Ridgetop wind strong from the West and alpine temperatures near -8. Freezing levels 1500 m.

Sunday: Ridgetop wind light to moderate from the southwest. Freezing levels 1300 m. 

Avalanche Summary

On Wednesday, one loose-wet avalanche size 1 was reported from a steep solar aspect.

On Tuesday, natural cornice falls were seen. Reports indicated that they did not pull a slab on the slope below. Sunshine may initiate loose wet avalanches on steep solar slopes and continue to weaken cornices.

Snowpack Summary

Surface hoar crystals can be found on Northerly aspects above 1800 m combined with dry wintery snow. On solar aspects and at lower elevations expect crusty snow in the morning and soft, moist snow in the afternoon. Large cornices may still pose a hazard close to alpine ridgelines, especially when it's warm and sunny.

A persistent weak layer of facets 40-60 cm deep that was buried in mid-February was reactive in the north of the region earlier this month but since the first week of March, only a couple of avalanches have been reported on this layer resulting from large triggers such as cornice fall. There are several other weak layers deeper in the snowpack composed of old surface hoar, facets and/or crusts, all of which have been recently unreactive.

Terrain and Travel

  • Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
  • Avoid exposure to slopes that have cornices overhead.
  • When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.
  • A moist or wet snow surface, pinwheeling and natural avalanches are all indicators of a weakening snowpack.

Problems

Cornices

An icon showing Cornices

Where cornices exist they pose a threat both from the potential to collapse under your feet (or machine) and from the potential to send large chunks of snow far down a slope. If anything can trigger the more stubborn persistent weak layers it's a large falling cornice. They are most likely to fail during intense periods of solar radiation. Cornice failures are very unpredicatble. 

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Mar 19th, 2021 4:00PM