Sea To Sky

Recent storm snow may need a bit longer to bond to the snowpack.

High -

WEDNESDAY NIGHT: Clear skies, freezing level below valley bottom.THURSDAY: Sunny with afternoon clouds, moderate northwest winds, alpine temperature -8 C, freezing level below valley bottom.FRIDAY: Cloudy with light snowfall, accumulation 5 cm, moderate west winds, alpine temperature -5 C, freezing level below valley bottom.SATURDAY: Cloudy with snowfall, accumulation 20 to 30 cm, strong southwest winds, alpine temperature -3 C, freezing level 1700 m.

Soft slabs from recent storm snow were reactive to skier activity on Tuesday, producing small (size 1) avalanches. Cornices were reactive to explosive control and some are separating from the ridge.

Around 15 cm of new snow fell on a weak layer of feathery surface hoar, 5 to 10 mm in size. The new snow will likely not bond well to this layer, allowing for snow to move easily, fast, and far. Snow amounts will be deepest in the lees of terrain features immediately adjacent to ridges.Below 1800 m, storm snow from last weekend may not be bonding well to an underlying crust (see here). In other areas, reports indicate that the recent snow is bonding well.Another weak layer of sugary facets and surface hoar lies around 150 to 200 cm deep in the snowpack. There hasn't been reports of avalanches on this layer for over a week. That being said, this layer may still exist in isolated areas around treeline in some portions of the region.At the base of the snowpack, weak and sugary facets are found below an early-season melt-freeze crust. This weak layer has been the culprit for sporadic, very large avalanches in alpine terrain in the past few weeks. The avalanches have occurred in areas where the ground roughness is very smooth, for example glaciers, firn, and shale/rock slab slopes. An avalanche could be triggered in this layer with a very large trigger, such as a cornice fall.