Coming out of a wild week of weather, the snowpack appears to have settled and bonded fairly well. Our biggest concern today is wind slabs, old and new, on Northeast aspects at mid and upper elevation. Persistent weak layers appear to be going to sleep, but don’t take that for granted. Continue to exercise caution in steep, unanchored terrain and take a quick moment to assess the strength of the upper snowpack as you travel.
With 2" to 4" of new snow and moderate southwesterly winds present friday, it is possible you will trigger new wind slabs below ridgelines, at the tops of chutes, or on cross loaded gullies at treeline and above. This means new small, soft wind slabs may form over top of, and mask, older hard slabs.
Weak layers from November and December are now buried deep in our snowpack.
As a forecaster this is a difficult one. While this is becoming increasingly difficult to find and showing little reactivity, the consequences of triggering a 3' deep persistent weak layer would be calamitous. I’m on the verge of letting this one go; but in light of this past week’s wild weather cycles, I still want more field data that shows this problem has gone dormant throughout the forecast zone before I drop it as a problem.
I recommend traveling on slopes <35°, avoid traveling below big convex rollovers and start zones, and be aware of terrain traps like gullies, cliffs and strainers below you.
Thursday we toured out the Eagle Peak area from Lookout towards Steven’s Peak. The warm temps and infusion of Christmas moisture, followed by below freezing temperatures Wednesday and Thursday nights appear to have firmed up the upper snowpack pretty well. We did not see failures in Extended Column Tests at either of our pit locations. Snowpit data from Silver Mountain Ski Patrol yesterday was showing propagation in the upper 30 cm's of the snowpack with hard force. Right now our main concern in the snowpack is surface instabilities resulting from new snow and wind. It only takes a minute to do a quick hand shear test or stability test in the upper snowpack and look for results.
I did find a weak layer buried deep in a heavily wind loaded, near ridgeline, NE aspect slope. It slid dramatically during a Propagation Saw Test. What this tells me is that there continue to be spatial variabilities in the snowpack that are hard to generalize—meaning get out and have some fun, but proceed with caution. Do not assume all slopes are stable just because you find one that is.
How about a New Year’s resolution to practice beacon search and partner rescue? You want those skills to be committed to muscle memory so you can still perform when you are jacked up on fear and adrenaline. All the local resorts have beacon parks now, and I let my kid hide a couple beacons in the backyard for me to find.
Please submit observations. They are really helpful.
Enjoy the new snow and Happy New Year!
