Avalanche Forecast

Issued: Mar 18th, 2021 4:00PM

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

Avalanche Canada swerner, Avalanche Canada

Email

 

New snow and strong wind may form isolated pockets of fresh wind slab.

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

Moderate - Forecast snowfall amounts are uncertain.

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 5-10 cm. Ridgetop wind moderate from the southwest and alpine temperatures near -5. Freezing levels 1300 m.

Friday: Cloudy with sunny periods and possibly 5-10 cm. Ridgetop wind strong from the southwest and freezing levels 1700 m.

Saturday: Snow 10 cm. Ridgetop wind strong from the West and alpine temperatures near -8. Freezing levels 1300 m.

Sunday: Snow 5-10 cm. Ridgetop wind light to moderate from the southwest. Freezing levels 1200 m. 

Avalanche Summary

On Wednesday, minimal avalanches were reported. A few loose-wet avalanches were seen on steep solar aspects below treeline. 

On Tuesday, a natural 1.5 loose wet avalanche was reported from steep rocky terrain and small loose-dry sluffs were easily triggered by skier traffic on northerly aspects. 

Snowpack Summary

Isolated wind slabs may form just below ridgelines with new snow and strong wind. Snow surfaces vary at the moment. Surface hoar up to 10 mm in size exists at treeline and above. Sunny skies and warm temperatures formed sun crusts on solar aspects and at all elevations and up to 2000 m on polar aspects. Dry snow still exists on north aspects at upper elevations. Large cornices loom over alpine ridgetops.

Persistent weak layers of surface hoar, crusts, and/or facets 80-120 cm down have recently been unreactive except for an explosives triggered avalanche in the southeast of the region on Saturday. 

Terrain and Travel

  • Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
  • Use caution above cliffs and terrain traps where even small avalanches may have severe consequences.
  • Cornices become weak with daytime heating or solar exposure.
  • When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.

Problems

Wind Slabs

An icon showing Wind Slabs

Increasing winds on Friday accompanied by 5-10 cm of new snow may form wind slabs in isolated alpine locations. Steep, convex slopes below alpine ridgetops are the most likely places to trigger these slabs. 

If the sun pokes out it may have enough punch to initiate the recent snow as loose wet or dry avalanches from steep terrain features. 

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Cornices

An icon showing Cornices

Periods of sunshine breaking through the clouds could pack enough punch to increase the likelihood of cornice failures. The best way to mitigate the risk is to minimize your exposure, especially when solar radiation is strong.

Aspects: North, North East, East, South East, North West.

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 3

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