Warming and solar induced avalanches are likely. Smaller wind slabs, storm slabs or cornice fall could "step down" and release persistent weak layers resulting in large avalanches.
Summary
Confidence
Moderate - Timing or intensity of solar radiation is uncertain
Weather Forecast
Drier, sunny conditions expected on Friday and then back to unsettled weather for the weekend.Friday: A mix of sun and cloud. Alpine temperatures near -2 and freezing levels 1900 m. Ridgetop winds light from the South.Saturday: Snow amounts 5-10 cm. Alpine temperatures near -23and freezing levels 1500 m. Ridgetop winds moderate -strong from the West.Sunday: Mix of sun and cloud. Alpine temperatures near -5 and freezing levels 1400 m. Ridgetop winds light with strong gusts from the West.
Avalanche Summary
On Wednesday, storm slabs proved to be reactive and ran naturally up to size 2.5 with a couple larger size 3 and 3.5. Storm slabs were also reportedly reactive to skier triggers up to size 1.5 at treeline elevations. On Friday natural avalanche activity will remain likely with the strong influence of solar radiation, warming and wind. Fragile cornices are also suspect which are a large enough to trigger deeper slabs to release on the slopes below. If you're traveling below treeline where the avalanche hazard may be lower than it is in the alpine you still need to be diligent with your terrain use and focus on potential overhead hazards by avoiding lingering in run-out zones where large avalanches to come from above.
Check out the recent Forecaster Blogs for more details.Snowpack Summary
30-50 cm of recent storm snow has accumulated at upper elevations. The new snow is dry up high and moist from 1800 m and below. This now brings 80-120 cm of accumulated snow which overlies a rain crust below 2000 m or a sun crust on solar aspects at higher elevations. New wind slabs are developing on leeward slopes and behind terrain features and large, fragile cornices exist along ridgelines. At higher elevations, the February weak layers are down 150-190 cm and woke up during last week's storm with many avalanches stepping down to them. The deep mid-December facet layer and November rain crust both still linger near the bottom of the snowpack and a few avalanches and cornice falls have also stepped down to these layers last week resulting in some very large full depth avalanches. These layers remain a concern during this stormy period ending with warmer temperatures and sunshine. The snowpack does not adjust well to change, and these deeper weak layers should remain on your radar through the forecast period.
swerner,
Avalanche Canada
