Avalanche near Elephant's Back

Around 12pm on 3/3/17, my partner and I descended the NE side of Elephant's Back in the Carson Pass area. We parked at Red Lake, skinned up along the old road to the pass, then descended on the northeast side of Elephant's back, north of the steep chutes coming off the summit. We observed partly cloudy skies, high winds generally from the SW and significant wind transport. On the first pitch of our descent, we observed no signs of instabilities in the snowpack (shooting cracks, whoomphing, other avalanches in the area, etc.) Prior to starting our tour, we drove to the pass, scoped out the terrain and conditions.

 

After dropping our first pitch with no issues, we trended E into a drainage S of Elephant's hump where my partner--who had skied the area a few times-- said there would be some great NE facing aspects that might not have the wind-textured sastrugi and suncrust mix of the higher elevations. We traversed around until we found a nice pitch to descend. We stopped atop a rollover, discussed a strategy--I would descend the rollover, then stop midway down to shoot some photos of my partner. Due to the avy advisory and the stable conditions over the past week, I felt secure in stopping midslope on a NE, loading aspect. We were below the area of my greatest concern and had seen nothing to indicate instability, except the wind transport.

I began my descent of the rollover making what I planned to be 4 turns. The snow was soft windboard. As I went to make my final right turn to set up for a shot, I felt a sense of vertigo. Much like an earthquake where the whole world moves and it takes a second to realize what is happening, I noticed a spray of snow, then realized that I was moving and the entire slope was cracking apart all around me. I shouted "avalanche! avalanche!", then took stock and just told myself to try and stay on top. After a few seconds, the avalanche stopped and I was still standing in the exact position that I had stopped after my final turn. I estimate that I slid a couple hundred feet downslope, close to 100 vertical feet. (see photos). It took a minute or so for my partner to appear at the top of the rollover to see what had happened. The high winds prevented him from hearing my shouts.

 

I sustained no injuries. My partner and I analyzed the situation, had lunch, then skied back to our car for a beer.

 

Analysis: My parter and I are fairly experienced bc skiers and locals. We've been skiing the Sierra for nearly 10 years and have avy certs. We tend to be conservative in our decision making. This morning we awoke, checked and discussed the advisory and changed our objective from Stevens Peak to Elephant's Back in hopes of avoiding a day of wind and blowing snow on ridgetops. 

 

This turned out to be the right call on the skin up and first pitch of the descent down. The entire day, we were impressed with the winds and spiraling snow devils marching down the lee snowfields of the crest. 

 

After our first descent of the area that most raised concern--just beneath Elephant's Back--I let my guard down for areas of concern, despite the loading. We traversed out and right, E, until we reached a nice, steep pitch. We communicated my plans for shooting a photo and also the terrain and conditions, agreeing to pitch it out. 

 

However, as I descended, I lost sight of my partner atop the rollover. After the incident, he never heard me shout and didn't realized that I triggered the slide until we convened below after everything had happened. My partner only saw me after he approached the rollover after some time without hearing my calls to descend so I could shoot and spot. 

 

I feel like we communicated well, checked in with available information prior to our tour and adjusted our plan based on conditions. We skied in a safe, pitched out manner. 

 

We should have never lost sight of each other, even on a small, apparently innocuous feature. My partner and I also agree that we should have also given more credence to the loading that was happening all around us.  As we observed the slidepath after the incident, we noticed that the crown had all but disappeared after an hour. Rapid loading was occurring on all lee slopes, both above and near treeline in the Carson Pass region.