Quick report
- Red Flags
- Poor Snowpack Structure
- Red Flags Comment
- <p>Main concern is the widespread, very weak faceted surface snow. Also a buried rime crust, and over all weak upper pack.</p>
Goal was to look at the surface snow on a variety of aspects and elevations before the incoming storm. Many thanks to the Snowbasin Patrol for showing me great spots and talking snow and weather!
About 8,600', northerly facing: the snow surface is a 8" to 10" thick layer of near surface facets, broken by a thin rime crust. Hand shears showed failure on weak snow beneath the crust. I would expect the first avalanche activity to be on the surface facets (shallow wind slabs Saturday, new snow slides Sunday). But as the storm continues, there is the potential for slides to break just below the rime crust, which would be deeper, wider and maybe more energetic. Top Photo.
About 7,600', northerly facing: again, a thick layer of near surface facets on the surface, capped with small surface hoar.. The rime crust was very intermittent. Also of note was another layer of weak facets, about 12 to 18 inches down. Hope that the surface hoar is destroyed by tomorrows wind and warmth, and perhaps even rain. However, expect the thick layer of near surface facets to be preserved. At this elevation, some "sand boxing" in shallower areas. Second Photo.
About 6,600', northerly: Once again, a faceted upper snow pack, capped with surface hoar. Unlikely for the rain and warmth to totally destroy the full depth of facets. Third photo.
We all love looking at the plumes below, produced by the University of Utah. These are for the Ben Lomond Peak area - the top graph is water, bottom graph is snow. It gives a feel for how the storm might evolve. They are updated every 24 hours. What I'm seeing is periods of snow, adding about 4" of water weight over 4 days. Of additional importance will be keeping track of the rain/snow line, WINDS (forecast to be strong) and periods of "peak intensity" - when it's snowing 2 or more inches an hour.
But looking like a good winter storm!
Snowpack
Shady slopes have consistent, deep near surface facets. Some capped with surface hoar at the lower elevations. Sun crusts were quite thin at the mid to upper elevations. Down at 6,600', the snow on very sunny slopes was wet and a little punchy, but not even any roller balls.