Avalanche Forecast
Issued: Apr 9th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
ahanna,
Avalanche Canada
Recently formed wind slabs may remain sensitive to triggering Saturday. The new snow will be prone to solar-triggered loose dry sluffing if the sun comes out.
Cornices and glide slabs are best managed by staying well away from them.
Summary
Confidence
High -
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: Up to 5 cm new snow. Moderate to strong southwest wind. Alpine temperature around -10. Freezing level 800 m.
Saturday: A mix of sun and cloud with convective flurries up to 10 cm. Ridgetop wind light to moderate from the northwest. Alpine temperatures around -10. Freezing levels 1000 m.Â
Sunday: A mix of sun and cloud. Light west wind. Alpine temperatures -8. Freezing levels 1400 m.
Monday: Sunny. Light east wind. Alpine temperatures -5. Freezing levels 1600 m.
Avalanche Summary
Most activity in the recent snow has been limited to loose dry sluffing. Wind slabs have shown quite limited reactivity in the last couple of days, the odd ski cut producing size 1-1.5. On Wednesday, a large size 3.5 wind slab was reported from a North aspect around 2400 m in the Glacier Park region.
A couple of natural cornice failures size 2.5 observed Thursday did not trigger slabs on slopes below.
Neighboring Glacier National Park reported a few very large (size 3-4) glide slab releases on Thursday. Glide slabs are hard to predict and can release at any time so it is important to avoid slopes with glide cracks.
Snowpack Summary
20-30 cm of new snow over the past few days has been wind affected in exposed alpine terrain, forming wind slabs in immediate lees of ridgetops. On North aspects in the alpine, the recent snow sits on dry wintery snow surfaces and possibly surface hoar on wind-sheltered slopes. Elsewhere, it sits on a series of melt-freeze crusts on all aspects below 1900 m and southerly aspects to mountain top. Reports indicate snow is 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
- Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
- 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.
- Keep in mind the crust offers an excellent bed surface for avalanches.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
Problems
Wind Slabs
Recently formed wind slabs may remain sensitive to human triggering Saturday.
Aspects: North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Apr 10th, 2021 4:00PM
