The March sun packs a punch and can quickly destabilize the snowpack on solar slopes.Storm slabs may continue to be reactive to human triggering, especially on leeward wind-loaded slopes.
Cornices are large and fragile. Solar radiation will weaken them further and cornice failures act as heavy triggers on slopes below.
Strong solar radiation may weaken the surface snow creating wet loose avalanches from steep solar slopes.
30 to 50 cm of new snow and strong south wind have formed storm slabs. These slabs may have a poor bond to the underlying crust.
Moderate to strong southwest winds have formed reactive wind slabs on lee slopes at treeline and above.
A layer of weak facets sits near the base of the snowpack. This layer is most likely to be problematic in steep, wind-loaded terrain where the snowpack depth varies from thick to thin. Especially in the northern part of the region around the Chilcotins, Birkenhead, and Hurley.
No new reports on Wednesday at the time of publishing.
On Tuesday, several skier-controlled slab avalanches (size 1.5) were reported on wind-loaded features at treeline and above. Dry loose sluffing was noted from steep northeast terrain up to size 1.5.
On Monday, several natural cornice falls were reported in the northern part of the region up to size 2.5.
On Sunday, a natural large size three, wind slab avalanche was observed. It started in a cross-loaded feature in the alpine and it may have stepped down to weaker buried layers.
Natural and human-triggered avalanche activity may occur throughout the week with rising freezing levels and solar radiation.
Surface snow will likely become moist on solar aspects during the day. 30 to 50 cm of recent storm snow sits above a sun crust on steep solar aspects, dryer low-density snow, and older faceted snow in sheltered areas. Much of this has been redistributed into reactive wind slabs at treeline and above. It has also built upon the large cornices that have already formed.
The mid-snowpack is well consolidated.
There is a widespread weak layer of large sugary facets at the bottom of the snowpack. Recent avalanche activity on this layer has been confined to northern parts of the region in the Chilcotins. This layer remains a concern in shallow snowpack areas.
Wednesday Night
Clear. Alpine temperatures near -11. Wind from the west 10 km/hr and freezing level valley bottom.
Thursday
A mix of sun. Alpine temperatures near -4. Winds southeast 10-20 km/hr. Freezing level 1600 m.
Friday
A mix of sun and cloud. Alpine temperatures near -3. Wind southeast 10-20 km/hr. Freezing level 1800 m.
Saturday
A mix of sun and cloud. Winds 10-20 km/hr from the south. Alpine temperatures near -2 with freezing levels 1900 m.
More details can be found in the Mountain Weather Forecast.
