60cm storm slab reactive to skier traffic on S aspect

We were a recreational party of 3 doing some pre-season reconnaissance skiing in the Valhalla Mountain Touring tenure. After digging a test profile on a NW aspect at 2100m and getting no significant results on the small facets found above the Nov 5 crust (which was under 60 cm of F-4F recent storm snow) we skied a 35 degree n-facing slope. When we transitioned to a south facing moderately treed start zone the storm snow was reactive and we triggered one size 1 and one small size 2 which took one of our party for a short ride into a tree. The crown width was approximately 15m, depth was 50-60cm and the failure plane was facets on the Nov 5 Cr. A narrow tongue of debris continued approx 100m vertical down the gully. We believe that the Moderate SW winds we observed during the day may have pressed the storm snow and contributed to a very subtly more cohesive slab compared to the North aspect.