Quick report
- Red Flags
- Wind Loading, Poor Snowpack Structure
- Red Flags Comment
- <p>Moderate to Strong winds blew all day and I observed light snow transport. There is not much snow available for transport right now, but the high winds are forecast to continue with tomorrow's snowfall. I am anticipating fresh wind slabs on all aspects on Tuesday.</p>
Snowpack
- Instability Comment
- <p>There hasn't been much change regarding our deeply buried persistent weak layer, because we haven't had a loading event since 2/9. I did some digging today to see if the facets have gained strength. I dug two Northerlies and one West facing pit. First the northerlies:</p> <p> </p> <p>This pit was on a NE facing slope below the treeline. I dug in the moraines below the Snaggletooth Chutes. At the base of the pack, I observed cupped facets showing some rounding that were 2 cm. They are F+ density. This layer did not produce any results, but I still have some concerns about this structure, and I think a big loading event could still produce full-depth avalanches down to this layer. I am also keeping my eyes on the layer at 100cm that produced a CT28 RP</p> <p> </p> <p>My other North facing pit was in the Middle Cirque Glades at 10,740 ft on a NE aspect. I wanted to see what the facets looked like if I gained a little elevation. Here I found a deeper snowpack with HS 170. I didn't draw a profile, I just wanted to check the hardness of the facets. From 0-32 they are 4F rounding facets and from 32-52 they are 1F- to 1F (bottom to top) rounding facets.</p> <p> </p> <p> </p> <p>This photo is interesting because you can see one of my old pit sites from 2/13 (at the far end of the slope) where the HS was 200 cm. Today's pit was 170, and I even probed 140 in another spot on this same slope. This really shows the variation of the depth across any given slope. </p> <p> </p> <p>I also wanted to check out the interface at the bottom of the recent graupel layer as reported by <a href="https://utahavalanchecenter.org/observation/84582">Tim Matthews and Nate Ament </a>. I did a compression test in each pit today, and I did not get results on this interface. It seems this problem has stabilized after a few days, which is typical for weaknesses associated with Graupel. </p> <p> </p> <p>My West facing pit was in the lower Funnel:</p> <p> </p> <p>The crust facet interface around 68 cm. that produced avalanches on 2/7 still has my attention. The 2/7 avalanche failed below the crust. At this point, the facets above the crust are weaker than the facets below the crust. Both have rounded edges. These layers did not react to a CT and ECT, but after both tests, I was able to get very clean shears above the crust (photo below).</p> <p> </p> <p>Strong winds are going to continue with the snowfall tomorrow. I am anticipating fresh drifts on all aspect, as the winds were really swirling from all directions today.</p>
A very mixed bag of surface snow conditions. Solar aspects have been hammered by sun and wind and are crusted over. The forecast is for temps to drop, and the new snow is supposed to come in cold and low density. I do not expect the new snow to bond well to the slick surfaces I found today on W, SW, and S aspects.
I found weak, loose, faceted snow on sparsely treed slopes near treeline on Northerly aspects. It was easy to initiate small sluffs on test slopes. This weak surface snow seems limited to treed slopes that are sheltered from the wind and receive small amounts of solar input. Any instabilities associated with this will be isolated to this specific type of terrain. More open Northerly facing slopes have been subjected to plenty of wind, and I did not encounter weak snow at the surface.