19 Dec 2011 - deep powder

I climbed to 2300m above the shizen koen in the Tsugaike area. Trail breaking at 1700m was in boot deep ski penetration. By 2200m it was a little over knee deep and dry. I tested a few small steep unsupported rolls and found shooting cracks that didn't go very far. There was very little wind transport evident, and no wind slab that I could find. No sudden settlement in the storm snow either. By about 1300hrs the wind from the south picked up to moderate gusts with scouring and transport to the north. At 2300m I recorded -10.2C, and it was snowing at 1-2cm all day. I saw one patch of blue sky for a few minutes.

I travelled on mostly protected ground and rounded features with little wind stripped snow, so the 111208 rain crust was deep. At 1950m it was down 160cm (the snow depth was 200cm at 1950m). This contrasts to a few days ago on the Happo ridge, where the rain crust along the sharper ridge line was only 10-30cm deep. There are reports from a few sources of cracking and other evidence of instability on the rain crust with the new snow loading. Thin snow is weak snow, so be careful crossing from scoured to loaded areas where that crust is near the surface. Slab avalanches are easier to trigger there, and they could propagate out into the deeper storm snow that has accumulated to form destructive slides.

For now, I am skiing gentle features anywhere I find that rain crust near the surface, especially now after this colder weather is getting to it and possibly weakening the bond with the snow layer on the crust. The crust is not above 2200m (check for yourself!) and the most storm snow has accumulated above 1800m. So there is your sweet zone for avalanches on that crust. The most wind effected sharp ridge with no anchors is the Happo ridge... so that is where I'd expect to find them.

No pictures from today's outing, but check out the weather map for christmas day! Cold, lots of snow.