The local avalanche danger may be higher in the north of the region where buried weak layers have recently produced large, destructive avalanches.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
Wednesday: Light flurries / Strong westerly winds / Alpine temperatures of about -13Thursday: 5-8cm of new snow / Moderate southerly winds / Alpine temperatures of about -10Friday: Overcast skies / Moderate westerly winds / Alpine temperatures of about -12
Avalanche Summary
There were no new reports of avalanche activity on Tuesday. An ACMG Mountain Conditions Report from Christmas day describes a slab avalanche failing on a steep, north facing slope at 2100m. The avalanche initially failed 40cm down from the surface, and then stepped down 110cm to the November crust. The size of the avalanche is unknown, but this speaks to the touchy nature of persistent slabs in the area. On Christmas eve, a skier was partially buried in a size 2 slab avalanche while skinning up a northeast facing slope at about 2000m. The failure plane of this avalanche is unknown although the depth (40cm) suggests the mid-December weak layer may have been the culprit. Check out the Mountain Information Network post for more details.
Snowpack Summary
Between 8-15cm of new snow has fallen in the past few days. Limited observations suggest there was little in the way of wind on Tuesday. However, strong winds forecast for Wednesday may redistribute the loose surface snow into new wind slabs in exposed higher elevation terrain. 20-50 cm of snow typically overlies the mid-December interface which consists of stiff wind affected snow, faceted (sugary) crystals, and surface hoar that formed in sheltered areas. The overlying slab appears to have a poor bond to these surfaces in some areas, especially in wind-affected terrain in the Dogtooth range and possibly Quartz Creek. In sheltered terrain, the overlying slab has remained soft. As it continues to settle and gain cohesion, we may start to see a more widespread persistent slab problem develop. The thick mid-November crust/ facet layer typically sits 70-140 cm down in the snowpack. Recent avalanche activity in the Dogtooth Range suggests this layer has woken up and has the potential for large avalanches. Check out this ACMG Mountain Conditions Report for more info: https://mountainconditions.com/reports/december-25th-dogtooth-range-november-crust-awakening
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.