Local snowpack and weather variations exist throughout the region. Be aware of conditions that are specific to your area and make observations continuously as you travel.
Confidence
Fair - Due to variable snowpack conditions
Weather Forecast
Friday: Moderate to locally heavy snowfall / Strong to extreme southwest winds / Freezing level at 1200mSaturday: Light snowfall / Moderate northwest winds / Freezing level at surfaceSunday: trace amounts of snow / Light southwest winds / Freezing level at 1000m
Avalanche Summary
A size 1.5 skier accidental slab avalanche was observed at treeline on Wednesday. The slide, which occurred on a northeast aspect, had a crown of 25cm and is reported to have released on the February 15th surface hoar.Two size 1.5 slab avalanches were triggered on Wenesday by natural cornice fall on a north aspect at treeline. The crown was between 40 and 50cm deep and is reported to have failed on the February 12th surface hoar.Increased avalanche activity is expected with weather forecast for Friday.
Snowpack Summary
Dribs and drabs of recent low density snow add to a slab which overlies reactive layers of surface hoar that were buried on February 12th and February 15th. These layers currently sit between 15 and 60cm below the surface. The slab may also be reactive on southerly aspects where buried sun crusts exist. Loading from new snow and wind on Friday may cause another cycle of natural activity, or an increased sensitivity to human triggers. There are older weak layers that are now buried down around 70-80 cms and also at about 110 cms. These layers have been less likely to trigger by skiers, but they may still be sensitive to large loads like avalanches in motion or cornice fall.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.