Avalanche Forecast

An offshore low continues to push in bands of warm and moist air during the upcoming days ahead of clearing mid-week. 

Sunday night: Snow flurries, 5 to 10 cm, light southwest ridge wind gusting moderate and alpine low temperature around -5C with freezing level 1100 - 1400 m.

Monday: Snow flurries, 5-15 cm, light south ridge wind gusting strong, alpine high temperatures around -3C and freezing levels 1500 m to 1800 m.

Tuesday: Cloudy with snow, 5 - 20 cm of new snow, light south ridge wind gusting strong, alpine high temperatures around -4C and freezing levels 800 m to 1700 m.

Wednesday: A mix of sun and clouds with isolated flurries, trace to 5 cm new snow, light south ridge wind gusting moderate, alpine high temperatures around -4C and freezing levels 700 m to 900 m.

Early reports from Sunday report touchy small (size 1) storm slab avalanches in the immediate lee of windy features that propagated far but did not have much mass. We anticipate a further deterioration in conditions with dense snow and moderate winds. A few small slab avalanches (size 1-1.5) were reported in the past few days on surface hoar. Check out this MIN on the 29th and this MIN on the 28th from near Kicking Horse. On the 28th near Golden, small but reactive new wind slabs and cornice growth was reported.  

We're continuing to track a layer of surface hoar from early January which was reactive in previous weeks. Refer to: MIN report 1 & MIN report 2 from Hope Creek on the 20th and MIN report 3 from the Quartz zone on the 14th.  

25-45 cm of forecast and recent snow will have accumulated by Monday afternoon. This recent snow arrived with light to moderate wind, warm temperatures and will have numerous storm interfaces, including another layer of surface hoar from Saturday that may serve as failure planes. Check out this MIN and this MIN from the south Purcells. All this recent snow sits on top of a known weak layer of widespread surface hoar, facets, sun crust and old wind surfaces from the last drought.   

Buried 50-90 cm is an older surface hoar and / or a thin melt crust from Jan 11th. This layer was more prominent in the north Purcells in sheltered, open slopes at treeline and may become reactive with incoming warm temperatures and snow.

Two deeper layers persist, though they have been recently unreactive. Down 100-150 cm lies the December weak surface hoar / crust / facet layers. Closer to the ground lies the early November crust facet complex. Though unlikely to trigger, caution for these layers remains with large loads in steep, shallow, rocky areas with a thin to thick snowpack or shallow areas below treeline.  

• In times of uncertainty conservative terrain choices are our best defense.
• Avalanche hazard is expected to to increase througout the day, think carefully about your egress.
• Be aware of the potential for larger than expected storm slabs due to the presence of buried surface hoar.
• Use conservative route selection and resist venturing out into complex terrain.
• Avoid shallow, rocky areas where the snowpack transitions from thick to thin.