Quick report
- Collapsing
- isolated
During our tour we travelled from 5800'-7700' through mostly SE-NE terrain. We noticed the snowpack becoming very dense and sticky at lower elevations. The morning started out with clear skies and intense solar radiation. Moderate winds from the SW began around 1100AM, and cloud heights quickly dropped to ~8000'. It remained overcast for the remainder of the day. Around noon, after our first run we observed an air temperature of -2C at 6600'. At the bottom of our second run at 6300' on a SW aspect the air temperature was -1C. While ascending an isolated piece of unsupported terrain approaching 35 degrees our group experienced a large whumpf. We also began to notice isolated cracking on the corners of our skin track with the top 10cm of snow forming into a slab. We avoided steep SW terrain for the remainder of our tour. Other signs of instability we observed included wind transported snow (forming very large cornices). A sun crust had formed on steep solars and was very noticeable during our ski out.
Avalanche
Our group observed a natural wind slab avalanche (SS-N-R1-D2) on an E-NE slope at 7600'. The slope angle in the start zone appeared to be approximately 35 degrees. We were unable to confidently observe the runout, some debris was visible in sparse trees roughly 200-300 feet below the crown.