Be cautious near shallow rocky areas, where a small slab could trigger buried weak layers resulting in large avalanches.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
The arctic outbreak continues with cold temperatures and no snow until Sunday at the earliest. WEDNESDAY: Dry and sunny and COLD. Winds light-moderate north/northeasterly 20-35 km/h. Temperatures between -16 and -28 Celcius!THURSDAY: A mix of sun and cloud. Wind light southwest. Temperatures between -13 and -24 Celcius. No precipitation. FRIDAY: A mix of sun and cloud. Wind becoming southwesterly 5-15 km/h. Temperatures between -12 and -20 Celcius. No precipitation.
Avalanche Summary
Recent avalanche activity seems to have tapered off with one natural wind slab (Size 1.5) observed on New Year's day on a NE aspect in the alpine near Fernie.
Snowpack Summary
The snow from last week is showing signs of consolidating into soft slabs and sits on a variety of wind-affected surfaces at treeline and in the alpine. That said, the main concern is windslabs (and some cornices) forming in the alpine due to the recent arctic outbreak winds. Deeper in the snowpack the mid-December persistent layer (facet interface) has been more prominent and reactive in the Corbin zone than closer to Fernie: Watch out for thinner snow packs and areas of crossloading in isolated areas (think shallow rocky areas) where an avalanche could step down to trigger deeper layers.
Problems
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.