Avalanche danger will increase dramatically above the rain line, especially on wind-affected slopes. Low angle sheltered terrain is recommended.
A frontal system leaving the region will leave reactive slabs above the rain line. Southern parts of the region could have 40-60 cm of snow forming a widespread storm slab problem on all steep slopes at upper elevations, while further north, slabs are most likely found on wind-loaded slopes. Strong alpine wind could still produce natural avalanches on freshly loaded alpine features.
Cooling temperatures across the region with the frontal system continuing to bring precipitation to southern parts of the region.
SUNDAY NIGHT: Continuous flurries in the south with 15-25 cm of snow above 1400 m (rain below) and 5-15 cm in the north, strong southwest wind, freezing level around 1400 m with treeline temperatures around -1 C.
MONDAY: Cloudy with flurries bringing another 5-10 cm around the Coquihalla and Allison Pass, mostly cloudy in the north, strong west wind, freezing level drops to 1000 m with treeline temperatures around -5 C.
TUESDAY: Mostly cloudy with scattered flurries and up to 5 cm of snow, moderate southwest wind, treeline temperatures around -6 C.
WEDNESDAY: Mix of sun and cloud, light wind, treeline temperatures around -8 C.
Avalanche observations are currently limited to reports from the start of the storm on Saturday and Sunday with thin storm slabs already showing signs of being reactive. There will likely be a natural avalanche cycle across many parts of the region on Sunday and Monday night. On Monday, storm slabs will be primed for human triggering at higher elevations, while natural activity may continue in the alpine. Danger will likely be greater in southern parts of the region that get more snow.
As the frontal system leaves the region on Monday there could be about 40-60 cm of fresh snow around the Coquihalla and Allison Pass but only 15-25 cm in northern parts of the region. Snowfall amounts will likely increase rapidly around treeline elevations once you get above the rain line (so will the hazard). Open terrain will be heavily wind affected, with very touchy slabs in lee terrain. Storm snow is sitting above crusts on many slopes, which in the short term could form a sliding surface for avalanches, but should bond relatively quickly.
Over the past month this region has had issues with several lingering weak layers, but recent weather has helped strengthen the snowpack. A crust layer around Allison Pass will now be roughly 100 cm deep and strengthening. There are no deeper layers of concern at the Coquihalla. In northern parts of the region old buried wind slabs on facets, along with a deeply buried crust from December, have become unreactive.
