Surface instabilities in John F. Stevens Canyon

Traveled to John F. Stevens Canyon to observe surface snow conditions following a potent Pacific storm and Arctic intrusion.

• At the trailhead (4400'), there was 8" of new low-density snow and graupel resting on a stout (~1" Knife hard) rain crust that formed 2/3/18. The top 3" of the surface was a soft slab (4F) which cracked on nearly every step for 800' vertical. This snow structure looks to be problematic with tonight's substantial precipitation. 
• The rain crust disappeared around 5300" with the new snow increasing to 12" thick at this elevation.
• I was unable to trigger a slab in the surface snow due to its lack of cohesion but was easily able to trigger dry loose slides on slopes steeper than 35 degrees. These slides ran fast and relatively far on the near-surface rain crust.
• Above 5500' the surface snow transitioned to a stiff slab (1F) that was stubborn to trigger on isolated rollovers. However, there were several steep consequential slopes that looked to be "sure bets" to slide that I stayed well away from.
• Moderate winds were transporting snow at mid and upper elevations throughout the tour.
• Visibility was poor but two small (D1) storm slabs were noted on SE aspects at mid elevations.