A widespread natural loose wet avalanche on west aspects below treeline occurred on Thursday. Warm temperatures into the alpine have destabilized the snowpack. Stay away from the steep slopes until temperatures cool down.
Weather Forecast
Light snow beginning Friday and continuing through weekend. Light SW winds will increase to moderate with snow. Freezing level close to 2000m on Friday then falling to Sunday. Major snow storm predicted for the beginning of the week.
Snowpack Summary
Continued warm temperatures softened alpine surface snow and weakened lower elevations snowpack making for moist/wet conditions. Slabs will persist at tree-line and above on North-Easterly aspects below ridge crests and cross-loaded terrain. The mid-pack is facetted, new snow interface is a concern along with a decomposed surface hoar down 40cm.
Avalanche Summary
Warm temperatures and strong solar induced a natural avalanche cycle again on Wed. afternoon. Numerous loose wet to sz 2 at lower elevations. Icefields Parkway was closed for control work on Thursday producing numerous loose wet avalanches to size 2 that crossed the highway and wet slabs that showed propagation up to 100m across.
Confidence
Timing of incoming weather systems is uncertain on Friday
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.
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.