Weather Summary:
This week the Whistler area was hit with multiple storm cycles and no significant breaks in the weather. On January 21st Whistler received 62cm's in 24 hours, this pattern continued throughout the week with daily snowfall ranging between 10-30cm. All of these systems were accompanied by moderate to extreme southerly winds. We observed seasonal temperatures, with freezing levels ranging from 400-900m.
The Duffey Lake area received the same storm systems with about 50% less snowfall accumulation.

Terrain Visited:
We did trips in the Musical Bumps off Whistler, and the Spearhead Glacier on Blackcomb. We also visited areas around Chief Pascal and Joffre north and east shoulder. We focused our attention on simple to challenging terrain from 1600- 2300m on all aspects. Notable avalanche problems include wind slab development on lee alpine and tree-line features with cross loading an all but south aspects. We avoided convex slopes, unsupported features and areas with wind loading. We also witnessed significant cornice development and avoided overhead hazard from steep rock and cornice threatened start zones.

Avalanche Summary:
Whistler Mountain reported numerous explosive controlled results over the week ranging from size 1-3.5 failing on the Jan 16th melt-freeze crust and Jan 6th melt-freeze crust. Skier triggered avalanches tended to be in the 1-1.5 size range and were confined to daily storm snow accumulations. In the Duffey Lakes area we saw evidence of a past natural avalanche cycle up to size 3 otherwise no new avalanches were observed.

Snowpack Summary:
With approximately 200cm of snow in the Whistler area during the last 7 days the snowpack was settling with increasing density as one probed deeper. Notable exceptions to this were pockets of wind slabs in lee exposed features at tree-line and alpine elevations. There is 50-70cm’s of fist resistance snow overlies an overall well settled snowpack. The January 16th melt-freeze crust is on the surface in scoured windward areas and up to 150 -300 cm in the loaded lee areas.

In the Duffy Lake area on Jan 24th we found the January 16th crust layer present more in the range of 60-80 cm’s below the surface. The January 6th crust layer is present 80-100 down, producing hard results and breaking down.

Ski Conditions:
Ski conditions in both the Whistler and Duffy backcountry areas were excellent in sheltered areas with ski penetration around 40cm and blower powder on most aspects. Moist snow below 1200m during the middle of the week turned to low density snow at those same elevations later in the week as temperatures cooled. Lee features in the alpine and tree-line provided good skiing despite slight wind effect while windward aspects which were scoured to previous crusts earlier in the week held an additional 30cm atop of them by yesterday afternoon. Early season hazards still exists at lower elevations but generally things are filling in very nicely. Good coverage was observed on the Spearhead Glacier. Given the weather conditions tree well and deep snow immersion was forefront in our minds as we charged through mostly forested terrain during this amazing week of skiing.

Posted on behalf of the students of the Thompson Rivers University Canadian Mountain and Ski Guide Program.