Benchmark Pit Report 01/10/12

Tuesday I made the most of the sunny afternoon to shoot up to the top of Benchmark, poke around and see what’s going on back in EV. Skinning out from Two Elk’s, it’s pretty obvious we are no where near the much needed snow pack to get things rolling in the back bowls. I love the sunshine, but seeing a brown-out on all the south facers that were caked deep only twelve months prior is a bit of a downer. Guess the snow is only hanging in the shade and baking in the sun. The slopes are littered with surface hoar, caused by the clear night’s frost and the sunshine baking bonds into weak facets.

Storms like this past Saturday’s is a little more what we could use three times a week for the rest of the month, but let’s face it, what’s here is now… and now we have a pretty weak snow pack.  Studying the avy roses of the CAIC, the weakest areas should lie on the east facing slopes in the Vail-Summit Zone. I decided that’s exactly where I would belay to a shaded 38 degree slope on the NE side of the tall pines that separate East Abe’s and the open east facing slopes of Benchmark.  Reason being, this is most likely where persistant weaknesses will remain throughout this season’s snow pack.

I harnessed up and tied in with the glacier line around a stout tree.  Please be clear, it is not my intention to rope off and start popping off slides on purpose.  A safety line is in every guide’s pack and is an extremely important tool for any back country traveler.  Not to mention, it is the 8th Commandment in Bruce Tremper’s “Staying Alive in Avalanche Terrain”:  “Thou shalt use a Belay rope!  Most serious avalanche professionals carry and use a belay rope.”

I am not an avalanche professional (yet), but I do posses the knowledge and self-preservation skills to have a 30m glacier line as a part of my BC toolkit.  Hopefully it’s a last resort preventative from crack, pop, pin-ball ride through trees and a push off a cliff.

I dug a pit in what could be the sweet spot of a likely starting zone.  During the careful descent amongst sloughing loose snow and little failures of the top layer my observations showed that there weren’t any cracks propagating off into the distance, but the small failures under my skis were enough to be wary of.

Got settled in, dug the “pit” and started to gather some data. There are presently as of 1/10/2012, 3:00pm above 11,400 ft. East Vail Proper, three layers to this shallow 70cm “snow pack”. The bottom 30cm is basically larger facets slightly bonded resting on depth hoar. The next 30-55/60cm are comprised of faceted loose grains and the very top layer 55-70cm is the last storm accumulation. The exposed snow is already riddled with surface hoar. Doesn’t look too great for the future, but some avi cycles are likely to occur with a big snow and flush this particular zone of some of those pesky white dragons for the time being.  The snow pack is constantly changing and this does not mean that those dragons will not creep back into the mix in the future.  So, beware.

An isolated column test resulted in the top 58-70cm layer failing after four shots from the wrist. Not too surprising, while the break was not completely a shear one (Q3). Four shots from the elbow failed at the 30-58cm range, again not a clean break (Q3). Under the right conditions, I’m sensing a collapse in these weaker layers after a good snowfall, or a human loads them.

For the real snow nerds out there (myself included), I measured the temps of the pack to see if there were any major gradients. Chose to use 20cm increments to measure within the noticeable layers and came up with 0 deg. Celsius at 10cm, -1.7 at 30cm, -3.4 at 50cm and -6 at 70cm. Towards the bottom 10-30cm that’s 8.5 deg/m, 17 deg/m in the middle
and 13 deg/m at the top. The numbers below 30cm represent a weak temp gradient (<10 deg. C/m). The rest of the snow pack has a strong temp gradient (>10 deg. C/m), and results in a loss of strength with facet formation.  Math aside, we have plenty of weak snow to make conditions unfavorable in the future.

Cautiously negotiating my away from terrain traps and cliff bands, I skied my way to the lower angled aspect of East Abe’s and made some really fun turns. Crossing the creek and sticking skier’s right, I rode through the deeper shaded snow amongst the short pines until the waterfall. The ride was sugary and mellow. After the falls, the traverse left into the woods and the scarcely packed ski trail was extremely variable. We definitely need some serious snow in those woods to make the ride back to the bus a little less rough. The last bit of the trail is packed down by some snowmobiles and make the last portion along the water tower a welcoming slide home.

Not bad for my first “benchmark to water tower” trip of the year. Grand from afar, far from grand. It will be interesting to see how the snow pack in the zone evolves and how conditions will change as our season trudges on. Glad I was able to take the afternoon for some recon and gauge conditions until the next storm. Until then, keep it safe and pray for more snow!