Sea To Sky

The current stable weather pattern will be interrupted by another Pacific frontal system impacting the Sea to Sky region starting sometime on Wednesday.

Moderate - Timing, track, or intensity of incoming weather system is uncertain on Thursday

TUESDAY: Mainly cloudy / Light west wind / Alpine temperature -6 C WEDNESDAY: Flurries, accumulation 5-10 cm / Light to moderate southwest wind / Alpine temperature -3 C / Freezing level 700 mTHURSDAY: Snow, accumulation 20-30 cm / Moderate to strong southwest wind / Alpine temperature 0 C / Freezing level 1600 m

Avalanche activity seems to have tapered off as temperatures have cooled off over the past few days. On Sunday there were reports of a few explosives controlled size 1-1.5 storm and windslabs. On Saturday reports indicated several explosives controlled size 2 storm and wind slabs in the alpine and tree line. Some of these avalanches were running on a layer of surface hoar buried around December 26. There was also a report of a size 3 storm slab avalanche that released sympathetically to an avalanche that was set of by an explosive about 30m away.

30-50 cm of recent new snow from the past 7 days potentially sits on a weak layer of feathery surface hoar in the tree lin. Snow amounts will be deepest and touchiest in the lee of terrain features immediately adjacent to ridges.Below 1800 m, around 50 cm of storm snow may not be bonding well to an underlying crust (see here).A weak layer of sugary facets and surface hoar lies around 150 to 200 cm deep in the snowpack. There have not 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.