Avalanche Forecast

Moderate - Timing or intensity of solar radiation is uncertain

WEDNESDAY: Mostly cloudy with a few sunny patches, light southeast winds, alpine temperature -5 C, freezing level 1500 m.THURSDAY: Mostly sunny, light southwest winds, alpine temperature -4 C, freezing level 1700 m.FRIDAY: Mostly cloudy, light southwest winds, alpine temperature -4 C, freezing level 1700 m.

On Monday, a large slab avalanche was noted in Duffey Lake Road region in alpine terrain.  It was likely triggered by a cornice fall during sunny and warm conditions.  The slab likely released on the weak layer described in the Snowpack Summary section.  Otherwise, whumphing and cracking were noted at ridgetop, failing 10 to 20 cm deep.Large (size 3) persistent slab avalanches were observed in the far north of the region over the weekend.  They were about 60 to 80 cm deep, on northwest to east aspects, between 1800 and 2200 m, and failed naturally on the weak surface hoar layer described in the Snowpack Summary section.  They propagated widely across the slopes.  Otherwise, many slides in the recent storm snow were observed, often triggered by cornice failures. 

20 to 40 cm of new snow, with the most near Coquihalla Highway, has been redistributed into lee terrain features from northeast switching to southwest winds.  This overlies variable surfaces, including wind slabs at high elevations, a sun crust on south aspects, and a temperature crust on all aspects up to at least 1900 m.  On ridges, cornices are reported to be large and fragile.A weak layer consisting of surface hoar, facets, and/or a melt-freeze crust from late March is now buried about 50 to 100 cm. This layer is spotty in its distribution and has recently produced large and destructive avalanches. It is mostly likely to be problematic on west, north, and east aspects between 1900 m and 2250 m.The mid and lower snowpack are well-settled and strong.