Observation: Boundary Creek

Observation Date
1/21/2016
Observer Name
Joey Dempster
Region
Uintas » Bear River Ranger District » East fork of Bear » Boundary Creek
Location Name or Route
Boundary Creek
Weather
Sky
Few
Weather Comments
Gorgeous day. High temp close to freezing, no wind, sun.
Snow Characteristics
Snow Surface Conditions
Powder
Snow Characteristics Comments

Due south faces probably got a little damp today, but not too bad. Northerly aspects remained cold and dry.

Red Flags
Red Flags
Poor Snowpack Structure
Red Flags Comments
I did not observe any of the wind related red flags from yesterday (1/20) in the area in which I skied today, mainly because of a choice to avoid wind affected terrain. However, digging revealed a massive 50cm layer of basal facets. It is bridged by a very strong 10cm crust, but it is definitely a red flag for structure. I would not have tested this structure on a 35+ slope.
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Same
Problem #1 Comments

As noted above, the depth hoar layer at the bottom of the snowpack is impressive in size. The overlying crust is also impressive for its strength (somewhere between pencil and knife hardness) and is undoubtedly capable of bridging if it is uninterrupted. It's very high (10,500ft) and North facing for a solar input melt-freeze crust, so I wonder if there was a rain event before the late december snowfall? That would help in determining how widespread the crust is. In any case, the facets remain a concern, bridging or not, due to their weakness. The crystals at the top of the layer are forming bonds, but they decrease with depth towards the ground, where the facets are large and completely incohesive still. Scary stuff that would keep me off slopes approaching 35 degrees. Luckily the powder riding is superb between 25 and 30 degrees.

Snow Profile
Aspect
Northwest
Elevation
10,500'
Slope Angle
27°
Comments

I found a very different snowpack today 1000 feet higher and with a more northerly aspect. The main take-away from this is that in the Uintas this year, as is often the case, variability is high and backcountry travelers need to make constant observations to detect changes with elevation, aspect, and location. Results in one area do not guarantee the same results in another drainage, or even on the other side of the same drainage!

In the Boundary Creek area, I measured 165cm of snow, which may be on the high side due to wind activity, but certainly the snowpack here is deep enough to bury most trees and stumps and provide an excellent base for riding.

The top of the snowpack was perfectly right-side up and with the new storm snow, conditions were as good as they get. I was able to find and ski snow that was totally unaffected by yesterday's wind and therefore presented low avalanche hazard. ECT30N.

The one problem with otherwise paradisiacal vision is the massive 50cm layer of depth hoar at the bottom of the snowpack. See description in "avalanche problem #1" section for details.

As usual when a hard-to-quantify weakness like this lurks deep in the snowpack, slope angle is key. I skied 30 degrees and under all day without fear. I would not have skied a 35 degree slope with this structure, even with the stout crust overlying the depth hoar.

I am calling today's hazard "moderate", understanding that there undoubtedly many places in which the hazard was higher. Tomorrow should be the same or better since most of the hazard today was related to wind. Of course shallow snowpack areas and repeater slide paths with shallow snow are in their own class. But in "normal" terrain, hazard will be low-moderate with the depth hoar caveat.

Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Moderate
Coordinates