The Icefields area appears to be more stable than Maligne and Whistler creek areas. Whumphing, remote triggering, and shooting cracks are occurring in these zones.
Weather Forecast
Wednesday will be cloudy, seasonal temperatures, and 1500m freezing level . A storm may bring 30mm of precipitation, strong winds, and rising freezing levels Wednesday evening into Friday morning. Likely rain lower elevations. Models are not agreeing but if this transpires, this will be a significant change.
Snowpack Summary
Variable snow depth above treeline. Expect wind slabs in lee and cross-loaded terrain above 2000m. The persistent slab is down 40-90cm. It is touchy in the Whistler/Portal areas even on low angle slopes but is stubborn in the Icefields with inconsistent stability test results. Lower elevation snowpack is facetted and weak.
Avalanche Summary
Tuesday's field patrol in the Icefields observed no new avalanches with good visibility. Previous reports of remotely triggered avalanches to size 2 on slope angles as little as 15 deg around Marmot Pass with whumphing and cracking. Whumphing also noted in the Maligne area. In contrast, no reports of any propagations in the Icefields area.
Confidence
Timing, track, or intensity of incoming weather system is uncertain on Thursday
Problems
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.
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.