Storm Slab on Incline Lake Peak

Today we went to Incline Lake Peak to look at yesterday's avalanche activity. While we skinned in, we noticed some small cracking in the storm snow - an indicator that storm snow instabilities might still be active. We also noticed graupel on the snow surface that could make it harder for tomorrow's snow to bond to the current surface.

When we reached the small steep sections on the NE side of Incline Lake Peak, we stepped back and chose to move carefully around that terrain. One of these steep sections held a small skier triggered avalanche from yesterday (original report here). We dug into the crown and found that 4-finger+ slab failed just above the old snow/new snow interface on fist hard decomposing storm snow. A snowpit test at the crown yielded unstable results (ECTP 21) and a ski cut on the small section of remaining snow above the avalanche released the hangfire. More data that the storm snow weakness remained active. 

We continued up to the top of the peak and found numerous broken cornices along the ridgeline. We also saw signs of shifting wind directions including scoured and sculpted surfaces and some wind loaded areas. We ski cut a few test slopes as we descended the ridge and some minor cracking in small wind slabs. Some of the cornices remained fragile. When we got down, we started back up and saw two more recent avalanches. We were able to access both of them with some careful terrain management. They both failed just above new/old interface on softer (fist hard) decomposing storm snow with a bit of graupel. The slab was 4-finger to 4-finger + in hardness. They both failed on steep (38-40 degree) E facing slopes. They also both looked like they had been human-triggered sometime on Saturday (photos here). 

Next we headed over to a 38-40 degree E facing test slope very similar to the places we had seen the other avalanches. We had several clues that this slope was likey unstable: recent avalanche activity, cracking while skinning, and unstable snowpit test results. This test slope also had a slightly rippled surface indicating it had some wind effect. Even though it was a small slope, we approached it carefully. First, we looked at it from a safe spot and assessed whether or not it even made sense to test the slope. On the skier's right, there was an easy way to cut across the top into lower angle terrain. Then we made sure that we could see the entire run-out zone and that no one was in it or approaching it. Next, we established safe places to watch each other. I stayed at the top behind a tree while my partner made a high cut across the slope to a safe spot. The slope cracked but did not release. With my partner watching from the safe spot, I made the second cut just below his and the slope released producing an avalanche similar to the others we had seen. It failed on the same soft (F hard) decomposing storm snow and graupel just above the base of the storm snow with a 12 to 14 inch crown.