Cooler temperatures and snowfall will shift concerns to new snow instabilities for Tuesday. Sunshine should be minimal, but expect anywhere sun hits new snow to show heightened instability.
Summary
Confidence
Moderate - Forecast snowfall amounts are uncertain
Weather Forecast
Monday night: Mainly cloudy with scattered flurries bringing a trace to 5 cm of new snow. Light southeast winds, increasing to strong southwest in the alpine.Tuesday: Mainly cloudy with scattered flurries bringing 5-15 cm of new snow, continuing overnight. Moderate to strong southwest winds. Alpine high temperatures around -4 with freezing levels to 1600 metres.Wednesday: A mix of sun and cloud with variable new snow totals of 10-25 cm. Light northeast winds. Alpine high temperatures around -2 with freezing levels to 1900 metres.Thursday: A mix of sun and cloud. Light northeast winds. Alpine high temperatures around -1 with freezing levels to 2000 metres.
Avalanche Summary
The wet loose avalanche cycle from last Sunday to Friday diminished as cooler, seasonal temperatures returned to the mountains on Saturday. Evidence of the cycle is widespread at all elevations, with recent avalanches up to size 3 found mostly on southeast to southwest aspects. A mix of persistent and wet slab avalanches were also triggered naturally, by skiers, and explosives on Thursday and Friday. These occurred on all aspects and generally at treeline and alpine elevations. They were most often 30 to 50 cm deep.Looking forward, cooling temperatures and inbound snowfall will shift concerns to new snow instabilities over the near term. These are likely to present initially as small new wind slabs forming on lee slopes at higher elevations. The re-emergence of the sun from Wednesday onward will shift us back into a spring pattern of loose wet avalanche concerns increasing with sun and warming each day.
Snowpack Summary
Light new snow amounts have been accumulating above a surface of melt-freeze crust in most areas above 1500 metres, with the exception of limited north aspects above 2000 metres, where it may bury settled dry snow. Below about 1500 metres, new snow will land on variably isothermal (slushy) and crusty surfaces.The remainder of the snowpack is generally consolidated and strong. Exceptions may exist on north aspects above 2000 m, where a gradually strengthening layer of faceted grains buried 40 to 60 cm deep may still be preserved below an overlying slab of old and hard wind-affected snow.
cgarritty,
Avalanche Canada
