Surface sluffing has the potential to knock you, or your buddies below you, over. Pay attention to how much snow is moving with you!
Weather Forecast
Forecasted amounts of snow will be light in Rogers Pass today, with perhaps 5cm falling today and 5-10cm tomorrow. Temperatures continue to moderate from last week's deep freeze, warming to around -7*C in the alpine. Winds should continue to be light/moderate from the SW.
Snowpack Summary
25cm of low density storm snow sits over the December 8 surface hoar layer at lower elevations and over variable wind slabs up high. The November 28 surface hoar layer is down around 35-40cm over a facetted mid and lower snowpack. The November 12 surface hoar layer is down 60-110cm.
Avalanche Summary
Several size 1.5-2.5 slab avalanches were observed from the steep start zones off Mt Tupper and Mt MacDonald yesterday. Sluffing of the low density surface snow was observed in unsupported terrain, steeper than 35 degrees.
Confidence
Forecast snowfall amounts are uncertain
Problems
Loose Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.
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.