Updated at 9 am. Another 20 cm of storm snow overnight! Reactive storm slabs and loose dry avalanches are likely.
Summary
Confidence
High -
Weather Forecast
Wednesday: Snow accumulations 5-10 cm with strong SW winds. Alpine temperatures high of -11.Thursday: Mostly cloudy with some flurries accompanied by strong SW winds. Alpine high of -8 and freezing levels 1300 m. Friday: Snow amounts 5-10 cm with moderate-strong ridgetop winds from the SW. Freezing levels rising to 1400 m.
Avalanche Summary
On Monday, numerous skier controlled wind slabs were reported up to size 1.5 at treeline and alpine elevations. The deep persistent slab problem is a low probability/high consequence scenario that warrants extra caution around large open slopes, especially in shallow snowpack areas. There was a report last Tuesday of a size 3.5 avalanche at Mt Hosmer in the Lizard/Flathead region that released on or stepped down to the deep weak layer near the ground. On Wednesday we had a report from the Lizard range of another size 3.0 deep persistent avalanche on a northeast aspect in the alpine.
Snowpack Summary
Another 20 cm overnight bringing the recent storm snow totals up to 50 cm since Saturday. The new storm snow will likely be redistributed to leeward slopes, building fresh wind slabs. The mid-pack in this region is well settled, but the bottom third of the snowpack is composed of weak facets (sugary crystals). Recent snow profile tests have produced moderate failures that released suddenly down 75 cm on the facetted crystals. In the Crowsnest North up to 45 cm of recent storm snow lies above various old surfaces. Near Elkford up to 30 cm of old storm snow sits above a melt/freeze crust. Approximately 100-120 cm of settled snow sits above the weak layer of sugary facets that developed during the cold spell in December. Snow profile tests indicate hard shears in this location where the facets are sitting on a hard wind crust.
swerner,
Avalanche Canada
