Heavy snowfall will make avalanche conditions very dangerous in alpine terrain and anywhere with more than 30 cm of new snow.
With 20 to 50 cm of new snow, natural avalanche activity is likely during the peak of the storm early on Wednesday morning. Storm slabs will be primed for human triggering throughout the day.
Fresh storm slabs are the main concern on Wednesday as natural avalanches are likely in alpine terrain and along ridgetops.
On Monday, a large (size 2) wind slab avalanche was triggered by skiers in the Spearhead range. It occurred below an alpine ridge on a southeast-facing slope. Several smaller slab avalanches were also reported over the weekend.
20 to 50 cm of new snow is expected on Wednesday. Thick storm slabs will form in open terrain, while sheltered terrain will likely have deep low density snow.
Prior to the storm, wind from various directions reshaped the alpine, forming some hard wind slabs and scouring down to a crust that is now 30 to 60 cm deep. There is potentially some weak snow buried beneath this crust, but there has not been evidence that this layer is problematic at this point.
Rocks and trees poke through a building snowpack that grows from 60 to 90 cm at treeline to 150 cm in the alpine. Much of the below treeline vegetation band is below the threshold for avalanches.
Tuesday night
Moderate to heavy snowfall with 15 to 30 cm by the morning, 40 to 60 km/h wind from the southeast, treeline temperatures around -10 °C.
Wednesday
Storm eases off mid-morning with some with light flurries in the afternoon, another 5 to 10 cm of snow throughout the day, 30 to 50 km/h wind from the south, treeline temperatures cool throughout the day to -15 °C.
ThursdaySunny skies, no precipitation, light wind from the northwest, treeline temperatures around -15 °C.
FridayMostly cloudy skies, no precipitation, light wind from the southeast, treeline temperatures warm to -10 °C.
More details can be found in the Mountain Weather Forecast.
