New snow and moderate winds may produce reactive wind slabs.
The persistent slab problem remains a concern. Choose terrain that has low consequences to manage this problem.
New snow will arrive with moderate southwest winds. Winds from earlier this week have been northeasterly. Wind slabs should be expected on all aspects at higher elevations.
We continue to see the occasional avalanche on a weak layer of surface hoar and facets buried about 100 cm deep. Resulting in avalanches that propagated for hundreds of metres. Some of them were remotely triggered from hundreds of metres away. The common trend is that they are on north-to-east aspects around 1500 to 1700 m in elevation.
No new avalanche observation since the weekend.
On Sunday, a size 1 wind slab was skier-triggered in a gully at treeline, reminding us that despite great riding in sheltered areas, reactive wind slabs still exist in more exposed areas. See the full report here.
A week ago, our field team observed debris from a previous large persistent slab avalanche. At least once a week evidence of large persistent slab avalanches is reported. Keep this in mind when traveling in the backcountry.
The new snow that arrived Thursday night will be falling on wind slabs on all aspects at higher elevations due to recent variable winds. Approximately 30 to 50 cm down a decomposing crust, up to 5 cm thick, can be found. It appears to be bonding well to layers above and below and is widespread up to 1300 m and isolated as high as 1700 m.
A weak layer of surface hoar and facets may be buried about 90 to 140 cm deep on north-to-east aspects. This layer may rest on a harder melt-freeze crust. Where preserved, this layer, if triggered, is capable of producing very large avalanches.
Thursday Night
Cloudy, up to 7 cm accumulation by morning, winds southwest 25 to 30 km/h, treeline temperatures around -20 ºC.
Friday
Cloudy with possible sunny breaks late in the afternoon, 5 cm accumulation late in the day, winds southwest 20 km/h, treeline temperatures -20 to -15 ºC.
Saturday
Cloudy with late day sun, up to 5 cm accumulation, winds north 15 to 20 km/h, treeline temperatures around -15 ºC.
Sunday
A mix of sun and cloud, trace accumulation, winds northeast 35 km/h, treeline temperatures -17 ºC.
More details can be found in the Mountain Weather Forecast.
