We rode in the Central Bear River Range today and found sensitive avalanche conditions. We had four soft slab avalanches release on us. The most significant of the four was about 18 inches deep and failed on the new/old snow interface. The avalanche was approximately 50 feet wide and failed on a 40 degree slope (this is an exposed cliff band earlier in the year). I was able to hop over the stauchwall at the bottom of the slab and outrun the slide. The slide came to a stop several hundred feet below where the slope mellowed out to less than a 30 degree slope. (see Pictures 1-4)

The other three slabs failed on the interface from yesterdays moist snow and last nights lighter snow. These three were all about 6-8 inches deep some as wide as 50 feet but all of them stopped as soon as the slope angle decreased to around 30 degrees. (see picture 5 and the first video) All of these were on east and southeast facing slopes, with steep starting zones which quickly mellowed out to 30 degree slopes. We’ll call these all test slopes…:)

We dug several pits. The first pit was on an east facing, 32 degree slope at around 9100 feet in elevation. The total snow depth in this area was 10+ feet deep. The shovel shear test showed many sensitive layers in the snow. Compression test showed a failure at 11 taps, 7 inches down, 17 taps at the new/old snow interface 18 inches down and 23 taps on faceted snow under a hard crust a couple of feet down. I was surprised at the ECT test results since we had already set off 4 slab avalanches on very similar slopes. As you can see in the video, there were several failures: ECTN 6 down 7 inches, ECTN 25 at faceted layer under the crust down a couple feet from the Surface.

Amy dug a pit on a 28 degree, northwest facing slope at around 9100 feet. She had similar results on the compression test, and Extended Column Tests. No propagation failures the ECTs which was totally different than what we found while riding where we had several slides propagate to 50 feet wide… Interesting. I guess that's why we also check test slopes before jumping onto big lines.