1/29/13 Yodelin High Avi danger
1/29/13
WA Stevens Pass
3583
1
AlmostAspen and I braved warming temps and heavy snowfall yesterday morn and lapped yodelin front side and back side (toward nordic trails). Dug a pit and did a Rutschblock and shovel test, poked around ect. I'm not as scientific as some but here's what we found. Yodelin north facing slopes were harboring 15-24 new and south/SE/E held 10-20 new. we dug a pit on the back side in a more wind loaded area. at pit site there was 20 inches of new with varying densities (mostly heavy) on top of a sun/inversion crust beneath which was the consolidated pack to base.
It's the top 20 that was concerning. Rutschblock failed before I could even put my full weight on the column. It did NOT slide on the crust but on a facet layer 10cm above the suncrust. I didn't have a magnifier but upon inspection the facets/frost were clear. Big facets and some still looking feathery 3-5mm in size. Shovel test revealed the same.
Did a ski cut on the only area we thought could slide (there was much less snow under cover of trees) but nothing went. Still the top 18 inches was somewhat consolidated and the 2 inch with facets on top was very cohesive and I could imagine an easy step down slab avalanche on windloaded open areas. the bond between the suncrust and the first layer of new that fell was not incredibly strong but did not seem to have facets on top of it. It appears this most recent storm cycle started with 2 inches or so, then cold and facets, then warm and wet on top. Good recipe for high avi danger.
It's the top 20 that was concerning. Rutschblock failed before I could even put my full weight on the column. It did NOT slide on the crust but on a facet layer 10cm above the suncrust. I didn't have a magnifier but upon inspection the facets/frost were clear. Big facets and some still looking feathery 3-5mm in size. Shovel test revealed the same.
Did a ski cut on the only area we thought could slide (there was much less snow under cover of trees) but nothing went. Still the top 18 inches was somewhat consolidated and the 2 inch with facets on top was very cohesive and I could imagine an easy step down slab avalanche on windloaded open areas. the bond between the suncrust and the first layer of new that fell was not incredibly strong but did not seem to have facets on top of it. It appears this most recent storm cycle started with 2 inches or so, then cold and facets, then warm and wet on top. Good recipe for high avi danger.
