Wind slabs formed on Sunday may remain sensitive to human triggering and west/northwest wind Tuesday could form fresh shallow wind slabs. Seek out wind sheltered terrain and avoid slopes with cornices hanging over them.
Summary
Confidence
Low - Timing, track, or intensity of incoming weather system is uncertain on Wednesday
Weather Forecast
A weak upper trough Tuesday should deliver a trace of snow and a shot of wind. A vigorous low makes landfall on Wednesday which has potential to bring significant precipitation. Unfortunately the weather models have not yet agreed on a solution with regard to track and intensity, but there will likely be less uncertainty as we get closer to Wednesday. Stay tuned for more details. TUESDAY: Broken cloud cover, freezing level around 750 m, moderate to strong west/northwest wind, 1 to 3 cm of snow.WEDNESDAY: Overcast, freezing level around 750 m, potentially strong to extreme south/southwest wind, latest model run shows about 10 cm of snow. Stay tuned for more details. THURSDAY: Scattered cloud cover, freezing level around 1000 m, light southeast wind, trace of snow possible.
Avalanche Summary
A lot of avalanche activity was reported on Sunday as the 25 to 40 cm of recent storm snow ran on the February 22nd weak layer. Control work produced numerous loose dry storm and wind slab avalanches to size 1.5 on a variety of aspects. A size 1.5 storm slab failed naturally on a steep roll on a northeast facing slope at 1600 m while a size 2.5 natural avalanche was reported from a southeast aspect of the Miller glacier at 2250 m.
Snowpack Summary
Storm totals from the weekend are between 25 and 55 cm. This snow was subject to strong to extreme winds out of the southeast, south and southwest on Sunday which formed fresh wind slabs that extend down to treeline. The new snow rests on the February 22nd interface which consists of old wind slabs, spotty surface hoar, facets and a sun crust on solar aspects. Recent testing has shown resistant planar shears at this interface which makes sense given the activity listed above. Beneath the February 22nd interface the snowpack is well settled and strong. Variable winds in the past month have produced cornices on all aspects. They will become touchier as they grow in size, as temperatures rise, and when they are subject to the strong late-winter sun on clear days.
ghelgeson,
Avalanche Canada
