The sun's warmth packs a punch at this time of year. Use extra caution during the heat of the day, especially on sun-exposed slopes and around cornices.
Weather Forecast
It feels like spring. Cold temp's give way to daytime warming, with freezing levels rising to 1700m by late afternoon. No new snow and scattered clouds today, with light ridge-top winds. More of the same Friday, with a minor storm rolling through early Saturday, bringing up to 10cm of snow, mod SW winds, and freezing levels around 1600m.
Snowpack Summary
Solar aspects, SE through W, have been cooked by the strong sun the last few days, and a breakable crust is present to near ridge-top elevations. Polar aspects have remained cool and dry. Soft slabs in the upper 50cm can be found near ridge crests. The Feb 10th surface hoar/suncrust is down 60-100cm and is much less reactive than a few days ago.
Avalanche Summary
One loose sz 2 avalanche was observed from the W face of Sir Donald yesterday. It did not trigger any deeper layers once it hit the fan below the face. No new activity was observed in the highway corridor. Of note earlier in the week, there were BIG (up to sz 4) avalanches in the Asulkan & Loop valleys, likely cornice-triggered by solar warming.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.