Avalanche Forecast

Issued: Apr 9th, 2021 4:00PM

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

Avalanche Canada ahanna, Avalanche Canada

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Recently formed wind slabs may remain sensitive to triggering Saturday. The new snow will be prone to loose dry point releases if the sun comes out.

Summary

Confidence

Moderate - Uncertainty is due to the limited number of field observations.

Weather Forecast

The unsettled weather begins to clear up over the weekend as a ridge of high pressure sets up over the province.

Friday Night: 5-10 cm new snow. Strong southwest winds at ridgetop. Freezing level valley bottom.

Saturday: A mix of sun and cloud with convective flurries. Ridgetop wind light from the northwest. Alpine temperatures near -10 and freezing levels 1000 m. 

Sunday: A mix of sun and cloud. Light ridgetop wind from the northwest. Alpine temperatures -10. Freezing levels 1300 m. 

Monday: Sunny. Light ridgetop wind from the northwest. Alpine temperatures -5. Freezing levels 1800 m. 

Avalanche Summary

We have not received any reports of avalanche activity since Wednesday when the North Rockies Field team reported and wind slab size 1 from an East aspect at treeline. By Friday wind slabs were reported to be stubborn.. 

Snowpack Summary

15-35 cm of new snow over the past few days has formed stubborn wind slabs on leeward slopes and behind terrain features at wind exposed elevations. The new snow sits on a series of widespread melt-freeze crusts on all aspects below 1900 m and southerly aspects to mountain top. On North aspects in the alpine, the new snow sits on dry wintery and wind-affected snow surfaces. Snow appears to be bonding well at these interfaces.

The recent warm weather is expected to have helped old persistent weak layers heal, including a few crusts buried over the last month as well as a facet layer 150 cm deep from the mid-February cold snap.

Terrain and Travel

  • Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
  • Be aware of the potential for loose avalanches in steep terrain where snow hasn't formed a slab.
  • Brief periods of sun could quickly initiate natural avalanche activity.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

Problems

Wind Slabs

An icon showing Wind Slabs

Recently formed wind slabs may remain sensitive to human triggering Saturday.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Cornices

An icon showing Cornices

Cornices are especially fragile this time of year, especially when the sun is out. Cornice falls are dangerous on their own and they can also trigger slabs on slopes below.

Aspects: North East, East, South East.

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 3

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