Avalanche Forecast
Issued: Apr 6th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Cornices.
swerner,
Avalanche Canada
Wintery weather returns with new snow and strong wind on Wednesday. Fresh pockets of wind slab may be reactive on lee slopes in the alpine.
Loose-dry avalanches will may occur from steep slopes and terrain features
Summary
Confidence
Weather Forecast
The higher snow amounts will likely exist in the Northern parts of the region.
Tuesday Night: Clear. Ridgetop wind light to moderate from the South and freezing levels 1200 m.
Wednesday: Snow amounts 5-15 cm. Ridgetop wind moderate from the southwest. Alpine temperatures near -1 and freezing levels 1600 m.
Thursday: Mix of sun and cloud with scattered flurries up to 5 cm. Ridgetop wind light from the southwest. Alpine temperatures near -1 and freezing levels 1400 m.
Friday: Snow 5-10 cm. Ridgetop wind moderate to strong from the South. Alpine temperatures near -5 and freezing levels 1400 m.
Avalanche Summary
On Monday, skier-controlled and natural size 1 slabs were failing within the recent storm snow on solar slopes. The terrain features were steep convex rolls.
Sunday several loose-dry and skier-triggered size 1.5 avalanches were reported. The reactivity mostly occurred during daytime warming from steep slopes within the new snow.
With forecast snow and strong southwest wind on Wednesday, wind slabs may be reactive on leeward slopes, and natural loose-dry sluffing may occur from steep slopes and terrain features.
Snowpack Summary
Winter weather returns with light forecast snow amounts accompanied by moderate wind through the forecast period. Fresh wind slabs may build through the day on Wednesday. The new snow sits above surface hoar crystals on sheltered north facing terrain above 1900 m, a series of melt-freeze crusts on all aspects below 1900 m, and a sun crust on the southerly aspects to mountain top. Below 1500 m a melt-freeze crust exists and the snowpack is quickly diminishing.Loose–dry sluffing will likely occur on steep slopes and terrain features where the new snow has a poor bond to the underlying old surfaces.
At alpine and treeline elevations, a few layers of note are buried 50-100 cm deep including a layer of small surface hoar crystals on shady, wind-sheltered aspects and a series of crusts on solar aspects and below 1800 m. Overall the snow seems to be bonding well to these interfaces, although there have been a few isolated avalanches running on deeper crust layers in the past week.
Terrain and Travel
- Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
- Use ridges or ribs to avoid areas of wind loaded snow.
- Be aware of the potential for loose avalanches in steep terrain where snow hasn't formed a slab.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
Problems
Wind Slabs
Wind slabs will be most likely be isolated to immediate lees of ridgecrests and roll-overs in wind exposed alpine terrain.
Loose-dry sluffing of the new snow can be expected from steeper slopes and terrain features.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Cornices
Cornices are especially fragile this time of year. Cornice falls are dangerous in their own right and they can also trigger slabs on slopes below.
Aspects: North, North East, East, South East.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Apr 7th, 2021 4:00PM
