Blog: Week in Review (Mar 10-17)

Greg Gagne

Week in Review - Greg Gagne

The past week has been highlighted by what hasn't happened, which is any resemblance of winter.

The most dominant ridging pattern of the otherwise excellent 2016/17 winter season has placed a stranglehold on the Wasatch. High and low temperatures observed this week at Alta guard station at 8800' in Little Cottonwood Canyon:

Saturday 3/11 46/28 Sunday 3/12 40/29 Monday 3/13 50/29 Tuesday 3/14 52/33 Wednesday 3/15 54/37 Thursday 3/16 51/34

As can be seen, it has been several days without below freezing temperatures.Other stations recorded much higher maximum and minimum temperatures throughout this period, reaching the upper 50's at many mountain locations, with overnight lows only dropping into the upper 30's and low 40's.

Warming temperatures causes melt water to move down through the snowpack. Ideally the snowpack allows the melt water to percolate through to the ground, however melt water will begin to move horizontally if it encounters a crust (i.e. a sun crust.) UAC director Mark Staples captured this phenomenon on Tuesday, spreading powdered Tang at the surface, and observing how it percolated until it encountered a crust:

South facing aspects began getting active with wet loose naturals on Tuesday. The waterfall coming out of White Pine Canyon in Little Cottonwood also began flowing on Wednesday. Despite the heat, wet activity began to settle down by Wednesday, an indication thesnowpackhas adjusted to the warming.

Photos of some wet loose avalanches from this past week include: [Mark White, John Climaco]

A glide avalanche was reported earlier this week from the Blue Ice area in Broads Fork: [Photo Sean Zimmerman-Wall]

Any thoughts on how our warm winter/rain events may improve our spring snowpack "plumbing" and reduce the probability of larger event activity by having some percolation channels established well before climax melt. Great to see folks whippin their tang out! Reminds me of this one time at bandcamp, when my friend Simon Trautman was studying wet slabs at montana state back at the turn of the century. Dry powder tang better than wet coffee for showing drainage without input of additional h2o. When does BD start charging 19.95 a packet for a sustainably sourced wet slab evaluation kit? Anyway, thanks for all the hard work! Love the weekly synopsis, super valuable to review trends!
Sun, 3/19/2017
<p>Thanks for the feedback. We&#39;ve gone through our first significant wet period and things didn&#39;t hit the fan, and drainage channels have likely been established. Am feeling ok about solar aspects. Upper elevation north aspects are starting to warm, though this will be delayed this coming week. Fortunately we have a generally unstructured snowpack on the north aspects, so if the warm up is progressive, I think we&#39;ll get through this ok. Something we have to deal with every year, and each season is different.</p>
Fri, 3/24/2017
could be the worst march in 10 years and after that great snowy 2 months yuk
a star
Wed, 3/22/2017