Sea To Sky

Another round of snow and wind will contribute to our storm slab problem on Tuesday. Persistent weaknesses deeper in the snowpack continue to be tested by increasing load and warmth.

Moderate -

Monday night: Flurries bringing approximately 10 cm of new snow. Rain below about 1200 metres. Moderate southwest winds. Tuesday: Flurries bringing approximately 15 cm of new snow, rain below about 1200 metres. Moderate to strong southwest winds. Freezing level to about 1600 metres with alpine temperatures around -1. Wednesday: Flurries bringing approximately 10 cm of new snow. Light to moderate southwest winds. Freezing level to 1200 metres with alpine temperatures around -3. Thursday: Continuing flurries bringing 5-10 cm of new snow. Light to moderate southwest winds. Freezing level to around 700 metres with alpine temperatures of -6.

Reports from Sunday include two explosives triggered Size 2 storm slabs. One of these featured a 60 cm crown fracture and is suspected to have stepped down to a deeper weak layer, quite possibly our mid-February interface.Reports from Saturday included observations of a natural avalanche cycle taking place in the afternoon and producing storm slab avalanches to Size 2 south of Callaghan Valley. Explosives control and ski cutting in the Whistler area yielded Size 1 storm slabs and cornice results to Size 2.A notable report from Friday detailed a remotely triggered Size 1.5 persistent slab south of the Callaghan. This avalanche released from a northeast aspect, had a crown fracture depth of about a metre, and highlights ongoing concern for weakness existing at our mid-February layer.Looking forward to Tuesday, expect deteriorating stability over the day as another round of snowfall and wind continues building fresh storm slabs into Tuesday afternoon. Also, while the bond at mid-February interface remains questionable, the possibility of large persistent slab avalanches remains a concern, especially as snow and wind load the snowpack.

Roughly 10 cm of new, wind affected snow lies over temperature affected surfaces below about 1700 metres over and wind affected surfaces at treeline and above. Below the surface, a wide-ranging 30-150 cm of layered recent storm snow has settled into a slab over the mid-February interface. In heavily wind affected areas this interface may present at the snow surface or as deep as 200 cm. With 5-20 cm of faceted, sugary snow above it, this mid-February layer continues to produce easy, sudden results in snowpack tests and remains a primary stability concern. We remain in an ongoing incremental loading scenario where even as this layer slowly heals, it is continually tested as new snow and wind load the snowpack. Below the crust layer, the mid and lower snowpack are well settled and strong.