A variety of weak layers continue to produce large human triggered avalanches. We're still managing a mid-winter snowpack at and above treeline that requires thoughtful terrain selection.
Summary
Confidence
High -
Weather Forecast
The current weather pattern looks more like February than April, but we will take it! Freezing levels are expected to rise just a bit over the next few days and light daily snowfall should continue through the weekend THURSDAY NIGHT: Freezing level around 500 m, light southwest wind, 2 to 8 cm of snow possible.FRIDAY: Broken cloud cover, freezing level beginning near valley bottom rising to about 1500 m, light southerly wind, trace of snow possible. SATURDAY: Overcast, freezing level beginning near valley bottom rising to around 1500 m, light southerly wind, 4 to 8 cm of snow possible. SUNDAY: Overcast, freezing level beginning around 500 m rising to about 1600 m, light west/southwest wind, 2 to 4 cm of snow possible.
Avalanche Summary
On Wednesday a skier remote triggered a size 2 storm slab on a southeast facing feature at 2300 m that failed on the mid-March Persistent Weak Layer (PWL). Loose wet activity was also reported in the afternoon, even on northeast facing slopes as high as 1700 m as temperatures warmed.On Tuesday a skier accidently triggered a size 1.5 persistent slab avalanche on an east facing slope at 2200 m with a crown 50 cm in depth. Two more avalanches to size 2 were remote triggered on a south/southeast facing slope between 2050 and 2150 m, likely running on the mid-March PWL. A cornice fall on a southeast facing feature around 2500 m produced a size 3 persistent slab that likely ran the night of April 1st.Reports from Monday include several storm slab avalanches from a variety of triggers ranging from size 1-2. Fracture depths of 20-40 cm indicate some of the shallower weak layers identified in our snowpack discussion as failure planes. More sporadic reactivity at the deeper mid-March PWL was observed in adjacent regions. Numerous small (size 1-1.5) and reportedly hard wind slabs were also triggered on various aspects with both explosives and ski cutting.
Snowpack Summary
Tuesday night's storm produced 10 cm of cold snow with very little wind.5 to 20 cm of snow fell Sunday night putting the storm total at 50 to 90 cm, with amounts that taper with elevation. The snowfall was initially accompanied by strong south winds followed by strong north winds, so a mix of old/stubborn as well as newer more reactive wind slabs can be found on a range of aspects at higher elevations.Below the wind-affected surface, a few regionally variable weak layers exist within the upper 20 to 50 cm of snow. Breaks in the storm allowed for the formation of sun crusts on sun exposed slopes as well as surface hoar on shaded aspects. The mid-March PWL consists of crust/surface hoar and is now buried up to a metre deep. This PWL continues to produce large human triggered avalanches daily. The potential for deep 'step down' avalanches can't be dismissed.Deeper persistent weak layers from January and December are still being observed by professionals, but are generally considered dormant.
ghelgeson,
Avalanche Canada
