Generations of Wind Slabs

We wanted to see the central Swan Range before this evening's storm rolls in. We found the wind slab problem covered in today's avalanche forecast, and watched fresh slabs beginning to form.

• We found wind slabs from the past few days below large cornices in the lee of most alpine ridgelines. They were stiff and took hard stomping or undercutting to get them to slide. We found hard drifts up to 18" thick which tapered gradually down the slope.
• We saw moderate southwest winds building soft new slabs on top of the older drifts with what little snow was available. These newer slabs were only a few inches thick and isolated, but were more sensitive and cracked around us on test slopes. If the wind and snow forecast comes through tonight, I expect these slabs to grow by tomorrow.
• We found the early February crusts down under 1 to 2 feet of soft, but settled snow. We did experience one collapse in the soft snow between the 2/5 and 2/1 crusts where they were closer to the surface. We didn't see any shooting cracks resulting from the collapse, but it's worth keeping in mind that an additional load may cause the upper crust to break.
• We were comfortable getting into steep, wind sheltered terrain. Only the top 2 inches of new snow sluffed from our turns and didn't run very far. I expect more loose dry snow to make larger sluffs if the storm verifies tonight.