Avalanche Forecast

Monday night: Clear, light northwest winds, alpine temperature -18 C. 

Tuesday: Increasing cloud, afternoon flurries with trace accumulations, light southwest winds, alpine high temperature -14 C.

Wednesday: Cloudy, 5-15 cm of snow, light southwest winds, gusting at ridge-top, alpine high temperature -7 C.

Thursday: Cloudy, 2-5 cm of snow, light west winds, alpine high temperature -4 C.

During the storm, numerous size 2-3.5 avalanches released naturally in the storm snow. These avalanches primarily occurred on leeward aspects and mainly at treeline and alpine elevations. Reports also indicate that cornices may be reaching their breaking point and may act as triggers for these avalanches. Below tree line, large wet loose avalanches were releasing naturally on Friday and into Saturday during the warm temperatures.

With continuous stormy weather over the past week, there have been a handful of notable natural avalanches breaking on more deeply buried weak layers. These were very large (size 3-4) avalanches releasing on slopes above 2200 m. Although the likelihood is decreasing in the aftermath of the storm, these avalanches are a reminder that a deeper instability may linger in shallow, rocky, alpine start zones where the snowpack transitions from thick to thin. Wind slab avalanches or cornice fall may have the potential to step-down to these layers. 

There have been substantial changes to the snowpack over the past few days from wind, snow, and warming. 30-70+ cm fell during the weekend storm at upper elevations (generally above 1900 m) with the higher amounts in the eastern half of the region. Strong winds originating from the southwest and shifting to the northwest created a tricky loading pattern above tree line and increased concern for cornice triggers. These winds drifted the snow into deeper, stiffer slabs on leeward terrain features that may be possible to human trigger. During a warming event Saturday night, rain saturated snow surfaces up to around 1900 m that have since formed a crust.

The mid and lower snowpack is generally well settled and strong. Although isolated, there are two deeper layers that may still persist. A layer surface hoar currently buried 100 to 180 cm deep from late December and a facet/crust layer from November near the ground. 

• Remember that the snowpack will be significantly different at higher elevations than lower down.
• Stay off recently wind loaded slopes until they have had a chance to stabilize.
• Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.