Quick report
- Red Flags
- Heavy Snowfall, Collapsing, Poor Snowpack Structure
- Red Flags Comment
- <p>30-35" of total snow on the NE/N/NW aspects. Structureless faceted or rounded snow make up most of the pack, capped with the Christmas rain/rime crust and today's new snow. You can still locally collapse the crust onto the facets in sheltered terrain. On southerly aspects it's grass, juniper and rocks with trace snow from the new storm. While this provides low avalanche risk, one might wish to buy stock in p-tex or kneepad companies before skiing it...or just pray for two plus feet of snow.</p>
With the thin, heterogeneous snowpack in the Bear Rivers, conditions will change rapidly tonight through the weekend. Avalanche danger will increase, but by how much depends on local snowpack and the impending storm. Careful terrain assessment and risk discussion prior to traveling are prudent right now. Lots of unique situations exist in the snowpack and we have the first major storm of 2014 on the way, so communicate with your party, assess snow liberally, and take advantage of safe, representative test slopes before committing to routes and lines.
Snowpack
- Instability Comment
- <p>With a new storm moving in, we're going to see storm snow stacking up on an otherwise weak, structureless snowpack. The rain/rime crust is thicker in the front of the range than up canyon, so bonding is unlikely. Assuming a decent storm, any storm snow that gains sufficient momentum could step down to the crust/facet interface and trigger slab avalanches.</p> <p>With the coming storm, slabs will form on top of existing weak snow. With the long high-pressure spell, faceted snow is as deep as 30" in some areas. Weaker structure exists around vegetation and rocks. Any pooled graupel from last weekend could easily provide a trigger point. In addition to steep slopes and roll-overs on moderate slopes, once exposed rocks where cavity hoar and graupel are now on the scene could trigger activity once buried. </p> <p>Wind slabs and small cornices should begin to form on leeward ridges/slopes over the next couple days, providing new complexity to the storm snow on crust-facet problem. We'll have to see what we get and how much wind comes with it.</p>
A few more inches of light snow cover the weekend's modest snowfall. Right now there are 3-4" on top of a brittle melt-freeze crust that caps our rotten snowpack. New storm snow was very poorly bonded. Skiing out via the side of steeper exit gullies had pretty good storm slough movement but insufficient depth to get much energy. A look in holes at the base of exposed rocks showed graupel pooling over cavity hoar. Once we have enough snow for a slab, fireworks should ensue.