Avalanche Forecast
Issued: Apr 7th, 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
Watch for reactivity in wind-affected snow this week as incremental snowfall continues to accumulate.
Summary
Confidence
Moderate - Forecast snowfall amounts are uncertain.
Weather Forecast
Wednesday night: Scattered flurries with up to 5 cm new snow. Moderate southwest wind. Treeline temperatures around -5 C. Freezing level valley bottom.
Thursday: Mostly cloudy skies with isolated flurries. Moderate southwest wind increasing into the evening. Treeline temperatures around -5 C. Freezing level 1200 m.
Friday: 5-15 cm new snow. Strong overnight wind easing to moderate southwest over the day. Treeline temperatures around -3 C. Freezing level 1400 m.
Saturday: 5-15 cm new snow overnight. Moderate northwest wind. Treeline temperatures around -5. Freezing level 1100 m.
Avalanche Summary
Reports from Monday and Tuesday include:
- Numerous loose wet avalanches size 1-2 on solar aspects and low elevations in the afternoon
- Numerous loose dry to size 1.5 on steep northerly alpine aspects
- Evidence of several large cornice failures but no slabs were triggered on slopes below
On Saturday the North Rockies field team reported a wind slab avalanche on an east-facing slope at Renshaw that was a few days old. Otherwise the only other recent reports of avalanches have been from a natural cycle of storm slab avalanches that occurred at the end of March in northern parts of the region.
Snowpack Summary
Crusty conditions on all but steep north facing terrain above 1700 m was reported in this MIN report from Tuesday. Another 5-15 cm forecast overnight Friday will add to the settling 10-30 cm that fell incrementally over the past week. This recent snow sits on crusts at lower elevations and on solar aspects. Unstable slabs may be found on wind loaded features at upper elevations.
Recent weather patterns have helped previous weak layers strengthen, including the mid-February facet layer that is now roughly 150 cm deep. However, it may still be possible to trigger avalanches on basal layers in shallow rocky terrain along the eastern slopes of the Rockies.
Terrain and Travel
- Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
- Be alert to conditions that change with aspect and elevation.
- 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 reactive to human triggers Thursday. On Friday, new snow and wind will likely form fresh and reactive slabs. At treeline, these may sit over a crust.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Apr 8th, 2021 4:00PM
