Avalanche Forecast
Issued: Mar 6th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
cgarritty,
Avalanche Canada
Watch for reactive new wind slabs formed (and forming) in leeward terrain features at treeline and above. Be ready to dial your terrain selection back if snowfall exceeds forecast amounts.
Summary
Confidence
Moderate -
Weather Forecast
SATURDAY NIGHT: Cloudy with isolated flurries and a trace of new snow. Light to moderate south winds.
SUNDAY: Cloudy with scattered flurries bringing 5-10 cm of new snow, continuing overnight. Light to moderate southwest winds. Alpine high temperatures around -8 with freezing levels around 1200 metres.
MONDAY: Mainly sunny. Light south winds. Alpine high temperatures around -8.
TUESDAY: Mainly sunny. Light variable winds shifting west. Alpine high temperatures around -7.
Avalanche Summary
We don't yet have observations from Friday night's snowfall, but about 15 cm of new snow was likely reactive where winds helped it to form slabs over the old surface. A bit more new snow and wind over Saturday night should keep these kinds of surface instabilities on your mind for Sunday.
Warm sunny weather between Wednesday and Friday resulted in a widespread cycle of wet loose avalanches on sun-exposed slopes. These were mostly small (size 1-1.5), but a few large (size 2.5) wet avalanches were also reported. Heating also caused some cornice and ice falls. Clouds and cooling temperatures will heal these problems.Â
The primary concern this weekend will be wind slabs forming on north and east facing slopes.
Snowpack Summary
About 15 cm of new snow over Friday night accumulated above moist and crusty interfaces that formed during the recent warm up. Some deeper accumulations can be expected in lee terrain features. High shaded terrain will have a mix of soft snow and some old buried wind slabs.Â
The lower snowpack has strengthened over the past week as previous persistent weak layers have become unreactive. The main layers that we had been tracking were a layer of facets that was buried in mid-February (60-100 cm deep) and a layer of surface hoar and/or crusts that was buried in late January (80-120 cm deep).
Terrain and Travel
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
- Seek out sheltered terrain where new snow hasn't been wind-affected.
Problems
Wind Slabs
Another weak frontal system will continue forming new wind slabs on north and east aspects through Saturday night and Sunday.
Aspects: North, North East, East, South East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 7th, 2021 4:00PM
