Fresh wind slab formation is expected Sunday in the alpine, but our main concern is still the surface hoar down 25 to 35 cm which is most prevalent between 1400 and 1800 m, this interface likely remains sensitive to human triggering.
Summary
Confidence
Moderate - Freezing levels are uncertain
Weather Forecast
Sunday marks the start of a pronounced ridge of high pressure that is expected to be with us through at least Tuesday. This period is marked by mostly clear skies, cooler temperatures and a lack of precipitation.SATURDAY NIGHT: Freezing level returning to valley bottom overnight, light southwest wind at most elevations, no precipitation expected.SUNDAY: Mostly clear skies, freezing level beginning at valley bottom rising to around 1000 m during the day, moderate to strong northwest wind, no precipitation expected.MONDAY: Mostly clear skies, freezing level at valley bottom, light northwest wind, no precipitation expected.TUESDAY: Mostly clear skies, freezing level at valley bottom, light variable wind, no precipitation expected.
Avalanche Summary
Several rider-triggered persistent slab and wind slab avalanches up to size 2 were reported over the last four days on all aspects. The persistent slab avalanches were most prevalent between approximately 1200 and 1800 m, although some were noted at higher elevations, including into the alpine. Winds have been out of the south switching to west/northwest in the last 72 hours, and wind slabs have been noted above 1800 m. Widespread dry loose sluffing from steeper terrain features has also been reported. Check out this
MIN report for a great overview of conditions including photos.
Snowpack Summary
20 to 35 cm of recent new snow sits above a layer of large feathery surface hoar crystals and a sun crust. The new snow has been settling into a thin but reactive slab above this weak layer, with enhanced reactivity noted at elevations between 1400 and 1800 m where the surface hoar is particularly well developed on all aspects. Until recently, in most sheltered places there was insufficient cohesion in the snow above the weak layer to form slab avalanches; reactivity was noted most in exposed areas where the wind had stiffened up the slab. The weekend temperature trend form warm to cold is expected to consolidate the upper snowpack but this layer of surface hoar will likely remain sensitive to human triggering. The middle and lower portions of the snowpack are generally well-settled and strong.
ghelgeson,
Avalanche Canada
