Northern San Juan
SnowpackAndrew Temple · Feb 16, 2018 · Northern San Juan
Weather
Overcast skies, temps 25-30, Snowing s-1 - s1
Snowpack
Traveled primarily on NW-SW aspects. In a open area near treeline we triggered a large rolling collapse that was approximately 250' in diameter with shooting cracks that turned all the corners of the terrain for over 450'. In a pit on a WNW aspect, HS 100cm, we observed a snowpack comprised of about 20cm of large dusty depth hoar on the ground, Fist-hard, , below a 60cm mid-pack slab of faceting rounds, 4 finger, and about 20cm of low density new snow and df's. Snowpack tests resulted in several repeated CTV, and ECTPV's down 80cm on the depth hoar as well as a ECTP12 down 60 on the Jan. 9 interface. Westerly aspects do in fact hold lots of persistent weaknesses right now and it seems that the likelihood of finding these is greater BTL and NTL. I think the hazard is higher below and near treeline than above. The previous wind events before the last few small storms scoured and stiffened the old snow surfaces, so well-distributed persistent weak layers are less common. It's easy to talk one's self into thinking that slab below treeline is too faceted to have propagation propensity but if your skis are supported and it's not total trap door, then the slab exists. Relatively mild nighttime temps have resulted in a slower-than-normal faceting process given the depth and time of year.