Windslab Avalanche in Kettle Peak

We were skinning from the Twin Lakes parking area at around 8am this morning with objective of skiing the East Couloir of Kettle Peak.  Going up the main valley, we noticed several small loose wet avalanches from the previous day(s).  Skiing up Little Slide Canyon, we noticed some cohesive windslab behavior.  Occasionally, when kick turning, a section of the fresh snow from the previous day would shift in a contiguous slab.  These shifts were very subtle and there were no propagating cracks or fractures observed.

Upon reaching the entrance to the East Couloir of Kettle Peak, we booted up the climber’s right side.  My partner and I decided this would be the safest route – avoiding some small wind loaded features on climbers left.  The boot up was quite pleasant and no instabilities were observed.  At the top of the couloir we transitioned back to skis and summited the peak. 

We skied the mellow slopes above the couloir and observed soft, slightly cohesive, snow conditions.  When we arrived at the entrance of the couloir we discussed the conditions and set out to ski the first half of the couloir one at a time.  I watched my partner ski down the first half of the couloir, signaling to me when he was in a safe spot and ready for me to ski down.   I skied the first half observing similar snow conditions to the slope we previously skied.  Half way down our planned section, I decided to ski skier’s right onto a steeper part of the slope.   At the time, my mind was focused on the skiing and the upcoming line.  I was excited for turns and failed to consider the following facts about the slope that I wanted to ski: 1) the local slope angle on the terrain was greater than the 30 degree line we had planned to ski, 2) the slope was obviously wind-loaded, 3) we had witnesses minor windslab activity on our skin up.  As I skied onto the slope, I released a D1R3 windslab avalanche at approximately 1pm.  The terrain was east facing.  The slab released below me and did not affect me.  My partner was in a safe location and was also unaffected.  The crown was approximately 18” and the avalanche ran down the steep slope, onto a flat section of the chute, and then over the remaining length of the chute.  The avalanche triggered, or cleared away, a cohesive layer of snow (with a depth of approximately 6”) in the main chute. 

We skied the bed surface one at a time.  Upon exiting the East Couloir we encountered a party of 2 skiers who were booting up the bootpack we had just set.  They avalanche ran to their left and they were unaffected