Sawatch
AvalancheJohn Mackinnon ยท Feb 2, 2014
Weather
Clear and sunny. Calm winds even at treeline. Strong solar radiation.
Snowpack
Observed rumbling collapses and shooting cracks on all aspects below treeline. We remotely triggered several small "slides" from over 25 meters away---however the slides never made it past gliding motion. These all occurred on very small test slopes. Also noticed many naturally occurring shooting cracks-- "spider cracks"-- on our drive up California Gulch. We observed less signs of instability near TL on SW aspects but did get one HUGE rumbling collapse at 11,800 feet. A test pit on a north aspect below treeline showed an HS of 110 cm. We found this past week's storm snow resting on a buried surface hoar layer. We observed ~40 cm of recent storm snow. Multiple compression tests revealed sudden "drops" on a depth hoar layer that comprised the bottom 40 cm of the snowpack. When the whole column failed near the ground the recent storm snow "popped" off the buried surface hoar layer when it hit the ground.
Avalanche
Observed a small slab avalanche that we estimated to be 24-36 hours old. It occurred naturally on a steep poorly supported roll on a west aspect below treeline. SS-N-R2-D1.5-O. Crown heights ~40 cm, ran about 25 meters vertical and 25 meters across.