Expect fresh wind slabs at ridge crest and in cross loaded terrain. Keep your head up - variable winds may have loaded unexpected features.
Deeper weak layers are still possible to trigger, stay away from large unsupported slopes and rocky start zones.
Westerly winds and fresh snow continue to build wind slabs in the alpine and treeline. Approach ridge crest and wind loaded features with caution, variable wind directions may create reverse loading patterns. Slabs will be most reactive if they sit on a smooth crust.
A reactive surface hoar layer exists 30-70cm deep in the Toby Creek drainage and surrounding areas. It is most prevalent between 1900-2400m. This interface may result in large avalanches with wider propagation and slabs that are more sensitive to human triggers.
A weak and reactive layer of facets and depth hoar exists at the base of the snowpack above 1900m. While this layer sits deep in the snowpack it has the potential of producing large and destructive avalanches.
Avoid thin and rocky start zones where this layer may sit closer to the surface, and big open slopes capable of producing large avalanches.
A front brings light snow and strong winds overnight. Wednesday afternoon will see clearing skies and calmer conditions as the front moves out, replaced by a weak high pressure system.
TUESDAY NIGHT: Snow beginning late evening with up to 5cm expected by Wednesday morning. Moderate to strong southwest winds. Freezing level valley bottom.
WEDNESDAY: 5-15cm over the day with strong westerly winds. Freezing level below 1000m, alpine highs of -8.
THURSDAY: Cloudy with up to 4cm of snow over the day. Winds ease to moderate westerlies. Freezing levels at valley bottom. Alpine highs of -8.
FRIDAY: Chance of flurries with moderate westerlies. Freezing level at valley bottom and alpine highs of -8.
Explosive control work near Golden on Sunday Dec 5th produced a size 2 slab avalanche that failed to ground in a steep and unsupported terrain feature. A naturally triggered size 3 was also observed on a west facing slope in the Northern zone of the Purcells, believed to have occurred around the 2nd of December.
Two Mountain Information Network (MIN) reports (MIN 1 and MIN 2) from Friday, Dec 3 in Quartz Creek report deep persistent avalanches failing at the base of the snowpack.
A MIN report submitted on Sunday Dec 5 from the Brewer Creek area reported a column test failure on the Nov 21 SH down 60cm. Several avalanches that occurred in the Toby Creek drainage are thought to have failed on the same layer. This is believed to be lurking around the Toby Creek drainage area, however data is sparse this early in the season and this layer is believed to extend to other areas.
20-50cm of low density snow sits over a supportive crust up to 2400m on all aspects. In the high alpine, storm snow sits on a variety of wind affected surfaces.
Westerly winds have redistributed new snow into deeper deposits in wind loaded features at higher elevations.
A surface hoar layer extends throughout the Toby Creek drainage and surrounding areas - down 30 to 70 cm in sheltered features at treeline and below. Recent snowpack tests have shown this layer to produce sudden propagating fractures. We have limited knowledge of the distribution of this layer, but suspect is its most prevalent between 1900-2400m.
A late October facet/crust layer of concern sits at the bottom of the snowpack above 1900m. This layer has been reactive to human and explosive triggers, producing large avalanches. This layer is widespread throughout the region and will likely continue to be a layer of concern.
Average snowpack depth at treeline is 100-180cm, with the deepest snowpack found near the Bugaboos.
