Avalanche Forecast

Moderate - A small change in the upper snowpack could dramatically change avalanche conditions.

WEDNESDAY NIGHT: Scattered flurries with up to 5 cm of snow, 40 km/h wind from the southwest, alpine temperatures drop to -8 C.

THURSDAY: Scattered flurries with 5-10 cm of snow, 40 km/h wind from the southwest , alpine high temperatures around -6 C.

FRIDAY: 20-30 cm of snow, 50-80 km/h wind from the southwest, alpine high temperatures around -2 C.

SATURDAY: Another 20-35 cm of snow by the morning then cloudy in the afternoon, 30-50 km/h wind from the southwest, alpine high temperatures around -2 C.

Heavy snowfall resulted in a cycle of natural avalanches on Tuesday (and potentially on Wednesday too). Numerous natural size 2 storm slab avalanches were reported on Tuesday, and both storm slabs and persistent slabs were reactive to human triggering. The human triggered storm slabs were typically 20-30 cm thick. A few larger persistent slab avalanches were triggered remotely on layers that were 30-50 cm deep. Recent persistent slab avalanche activity has occurred on a range of aspects and elevations, suggesting the problem is widespread.

Expect human triggered avalanches to be likely in the coming days as the load continues to build over a recently buried layer of surface hoar.

A continuous pulse of storms has delivered 20-30 cm of fresh snow to the South Columbias over the past few days. 30-60 cm of recent snow now sits above a widespread layer of large, feathery surface hoar crystals. New snow is expected to continue to accumulate above this layer over the next few days and possibly make it more sensitive to human-triggering.

A weak layer formed in late November is now buried around 1 m below the surface. This is the layer of concern relating to the listed persistent slab avalanche problem. The weak layer may present as surface hoar, a crust, facets or a combination, depending on elevation and aspect. Below this, a variety of crusts from late October are buried deeper in the snowpack.