Don't let good weather lure you into dangerous terrain.
Dry storm snow may be seeing its first test of strong sun, and avalanche danger could increase rapidly.
30 to 70 cm od recent storm snow and southerly winds have formed wind slabs in lee and cross-loaded terrain at treeline and above.
Recent storms have formed large and fragile cornices. Be especially cautious during periods of strong sun, natural cornice failures have the potential to initiate large slab avalanches on the slopes below.
Strong solar input may rapidly impact the surface snow, initiating dry loose avalanches from steep terrain.
A natural avalanche cycle occurred over the weekend. Storm and wind slabs up to size 3 were observed at treeline and above. Cornice failures initiated large slabs on the slope below. Check out this MCR for a report from the Pemberton Icefield.
On Monday, explosive control in the Whistler area produced numerous large (size 2-3) storm and wind slabs, predominantly from wind-loaded alpine terrain. Check out Wayne Flann's blog for photos of these avalanches.
Looking forward to Wednesday, we suspect that rider-triggerable wind slabs may still be found at treeline and above. Strong sun could rapidly increase avalanche danger. Be cautious during periods of strong solar input, especially on slopes with large cornices overhead.
Up to 70 cm of recent storm snow was accompanied by strong to extreme southerly winds, forming wind slabs on west through east aspects at treeline and above. These winds have also scoured exposed windward slopes. A crust exists on or near the surface at lower elevations and to ridgetop on solar aspects.
A crust from early April can be found down 50 to 80 cm on all solar aspects and at treeline and below on north-facing terrain. Below this crust, the snowpack is generally well-settled.
Tuesday night
Clear periods. Alpine temperatures drop to a low of -9 °C. Ridge wind light from the west. Freezing level at valley bottom.
Wednesday
Sunny with cloudy periods. Alpine temperatures reach a high of -3 °C. Ridge wind light from the north. Freezing level rises to 1600 metres.
Thursday
Mainly cloudy with scattered flurries, up to 5 cm accumulation. Alpine temperatures reach a high of -5 °C. Ridge wind 15 to 30 km/h from the southwest. Freezing level rises to 1200 metres.
Friday
A mix of sun and cloud. Alpine temperatures reach a high of -3 °C. Ridge wind 10 to 40 km/h from the southwest. Freezing level rises to 1500 metres.
More details can be found in the Mountain Weather Forecast.
