Avalanche danger could spike to HIGH in any areas receiving direct sunshine.
Summary
Confidence
Fair - Timing or intensity of solar radiation is uncertain on Monday
Weather Forecast
Monday: Mainly sunny with light south-westerly winds. Freezing level rising to around 1300m in the afternoon.Tuesday: Clouds and then light (or locally moderate) snow beginning in the early morning. Winds increasing. Freezing level near 1000m in the afternoon.Wednesday: Light snow continuing. Light to moderate winds. Freezing level near 1000m in the afternoon.
Avalanche Summary
On Sunday, a size 3 loose avalanche failed naturally with solar warming on a south-east aspect in the Coquihalla area. A size 3 slab also failed on a north aspect, 1.5m deep and 100m wide. A few isolated avalanches were observed on Saturday in steep, rocky terrain. On Thursday, a natural loose moist avalanche cycle was observed in the Coquihalla region between 1400-1700m, with avalanches of size 2-3.5. A few slabs also released, with crowns of 50-60 cm. Explosives testing in the Duffey Lake area produced slab avalanches up to size 2.5 and skiers triggered very touchy storm slabs to size 1.5. Avalanche activity may increase again with solar warming on Monday, or with snow and wind on Tuesday.
Snowpack Summary
Recent storm snow created slabs at all elevations, which appear to have gained strength. Strong southerly winds left wind slabs behind ridgelines and terrain breaks. Large cornices loom and threaten slopes below. Crusts down 50-60 cm can be found on solar aspects in the Duffey Lake, Chilcotin, and Coquihalla areas. These exhibit moderate to hard, sudden results in snowpack tests.Deeper persistent weak layers are variable in distribution across the region. A crust/surface hoar/facet layer buried in early February, now down about 1.5m, is still is a key concern. It is especially prevalent on south-facing slopes above treeline, and all slopes below treeline. Although the likelihood of triggering this layer has decreased, the potential for surprisingly large avalanches remains.
pgoddard,
Avalanche Canada
