Avalanche Forecast

Fair - Forecast snowfall amounts are uncertain

Tonight and Tuesday: Moderate snowfall - 5-15cm tonight and an additional 10-20cm tomorrow. Winds increase to moderate-strong from the west. The freezing level (FL) is near valley bottom tonight rising to 1200-1500m on Tuesday. Wednesday: Continued moderate snowfall - 5-15cm. FL dropping to 800-1000m. Winds should be moderate-strong from the west-northwest. Thursday: Cooler and drier under a brief ridge of high pressure. FL dropping to around 500m.

Many areas have reported natural and easily triggered soft slab avalanches up to size 2.5. Most of these avalanches were 20-40cm deep and released on the Feb. 16 surface hoar layers, with some releasing on the Feb. 8 surface hoar/ facet/ sun crust interface. A few avalanches were triggered from a distance. The size and likelihood of avalanches should continue to increase with continued incremental loading and particularly with any increase in winds.

The upper snowpack is quite complex and we could see enough precipitation and wind early this week to tip the scales to more widespread and larger avalanches. Up to 40cm of low density new snow now sits on the February 16th Surface Hoar layer. The February 8th weakness is now down 50-70cm. Feb. 8th is used to describe a combination of weak layers: In most locations it marks a widespread surface hoar layer. On steep south & west facing aspects a sun crust that formed during the drought was also buried on Feb. 8th. This crust likely has a bit of faceting below it too, meaning that most terrain in the region has a weak layer 40-60cm under the snow surface. Below this problematic interface a well settled mid pack is in place. The exception is the eastern and southern parts of the region where deeper weaknesses and basal facets may still be a factor. In these areas, a low-probability/high-consequence condition exists. It should be noted that large cornices remain widespread throughout the region.