Avalanche Forecast

This MIN report from Saturday includes reports of numerous small storm slab avalanches but also shows an avalanche stepping down to an older weak layer.

On Saturday in the south of the region, numerous natural storm slabs up to size 2 were reported. In the north, a natural size 1.5 storm slab was reported and a size 1.5 storm slab was remotely triggered from 7 m away which was 30 cm thick. Around Bear Pass, a few natural wind slabs up to size 2 were observed. An assortment of natural loose dry activity was also reported.

This MIN report from Friday shows a small wind slab avalanche with a relatively wide propagation given the thin slab and suggests a poor bond between the new snow and the old surface.

The new storm snow has buried a highly variable snow surface that had formed during the recent period of extended cold temperatures and outflow winds. This newly buried weak layer consists of widespread facets, patchy surface hoar in sheltered terrain, and heavily wind-affected surfaces in exposed terrain including wind-scoured and wind-pressed surfaces, old hard wind slabs, and sastrugi.

A layer of large surface hoar crystals, buried in early December, was found down 20 to 50 cm prior to the storm. This layer has previously produced small but remotely-triggered avalanches.

The lower snowpack is well consolidated below a crust that had formed in mid-November which can be found below around 1200 m elevation.

Both the early-December surface hoar and mid-November crust have been dormant recently but could wake up with the new load from the storm snow, and avalanches have the potential to step down to these deeper layers.

A series of storm systems continues to impact the region with another wave of precipitation expected to arrive late Monday morning.

Sunday night

Precipitation 8-16 mm tapering off overnight, strong S-SW wind, freezing level around 1500 m with a potential inversion.

Monday

Precipitation 10-20 mm with potentially higher amounts for the SW of the region, strong SE-S wind, freezing level around 1500 falling to around 1000 m in the afternoon.

Tuesday

Mainly cloudy with a chance of isolated sunny breaks, moderate NE wind, freezing levels generally falling to around 500 m or lower.

Wednesday

Cloudy with light flurries, moderate SW wind, treeline high around -3 °C.

More details can be found in the Mountain Weather Forecast.

• Continue to make conservative terrain choices while the storm snow settles and stabilizes.
• Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
• Storm slabs in motion may step down to deeper layers resulting in large avalanches.
• The more the snow feels like a slurpy, the more likely loose wet avalanches will become.