Avalanche Forecast

Moderate - Timing or intensity of solar radiation is uncertain

A mix of sun and cloud is expected for Sunday with light intermittent flurries possible. Freezing levels are expected to fall to valley bottom overnight and climb to around 800m on Sunday afternoon. Alpine winds are forecast to be light from the northwest. Light snowfall is forecast for Monday but less than 5cm is expected. Freezing levels are expected to reach around 1000m on Monday and alpine winds are forecast to be moderate from the west to northwest. Similar conditions are expected for Tuesday with light snowfall, cool temperatures, and moderate west winds.

On Friday, numerous natural avalanches up to size 2.5 were reported in the region. Many of these avalanches were reported to have started in steep unskiable terrain or big faces and were typically starting as dry slabs and entraining moist snow below 1700-1800m. Three skier triggered avalanches were also reported. One was remotely triggered from 10m away on an east aspect at 2000m. This released down 70cm suggesting it failed on the early January surface hoar layer. A size 1.5 was reported on a west aspect at 1900m failing down 100cm on the early January layer. The third was a size 1.5 on a northeast aspect at 1800m failing down 40cm also on the early January layer. Natural activity is generally not expected on Sunday but could be possible on steep south facing slopes if the sun comes out in full strength in the afternoon. Newly formed storm slabs and a recently reactive persistent slab are both expected to be sensitive to human-triggering on Sunday.

Recent snowfall and strong winds created storm slabs in many places and wind slabs on features lee to the southerly winds. This new snow has also added load and stress to the already volatile persistent slab. A layer of surface hoar from mid-January is expected to underlie recently formed storm slabs in many areas. The recently destructive layers of surface hoar from early-January are now typically down 70-120cm and remain highly reactive. These layers have the potential for wide propagations and remote triggering, and smaller avalanches have the potential to easily step-down to one of these layers. The mid and lower snowpack are generally strong and well settled below these layers. Snowpack depths are variable across the region and shallow snowpack areas may have weak facetted crystals near the ground.