Observation: Chalk Creek

Observation Date
1/27/2019
Observer Name
Bo Torrey, Andrew Nassetta
Region
Uintas » Upper Weber Canyon » 1000 Peaks » Chalk Creek
Location Name or Route
Chalk Creek/ Humpy Peak
Red Flags
Red Flags
Recent Avalanches
Wind Loading
Collapsing
Poor Snowpack Structure
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Same
Problem #1 Comments
In the past 9 days, there have been 2 avalanche fatalities in Utah. Both fatalities involved Persistent Slab Avalanches. You can view those accident reports here - Moab & Skyline.
A Persistent Slab Avalanche problem should make you pay attention and approach slopes with caution. Avalanches are breaking 2'-6'+ feet deep and hundreds of feet wide throughout the Uinta Range. Last weeks storms and wind events added a significant load of snow that overloaded weak layers in our snowpack. Some slopes avalanched naturally early last week- during the storm, other slopes are hanging in balance waiting to be triggered.
With a Persistent Slab Avalanche problem, it is unlikely that you will experience any obvious signs of instability while out riding (such as collapsing or cracking) The most important thing to pay attention to is the fact that there have been multiple human-triggered avalanches over the past 3 days throughout the range.
We went out to Chalk Creek to have a look at a recent sled triggered avalanche off of Humpy Peak. Ted Scroggin was out here yesterday and has great photos and video of the slide. Check out his observation here. This avalanche averaged 3'-4' feet deep and broke nearly 500' feet wide.
The area where the avalanche broke is steep, rocky, wind loaded terrain with large stands of trees. We are glad that the party was able to escape without incident and thankful to them for reporting the avalanche.
Steep, upper elevation, wind loaded slopes on Northwest through East, through South East are where you're most likely to trigger these avalanches.
Avalanche Problem #2
Problem
Wind Drifted Snow
Trend
Increasing Danger
Problem #2 Comments
West winds picked up today around noon. Noticed drifting snow on exposed terrain. Would expect to find wind loaded slopes on the eastern side of the compass tomorrow. Wind transported snow will add additional stress to the buried Persistent Weak Layers.
Snow Profile
Aspect
East
Elevation
10,100'
Comments
Coverage is quite good throughout the area. We found soft riding conditions on mid-elevation sheltered slopes away from the wind. South aspects have developed a melt freeze crust. In several areas we found surface hoar and facets developing on the surface.
In some test pits it was very easy to initiate failures and in others, it was more difficult. The common theme among all of the tests was that they were breaking deep in the snowpack on old snow. This tells me that in some areas, the avalanches might be less sensitive to trigger but if you trigger an avalanche it will break deep.
CT 11 Q1 @ 50 cm
ECTP 21 @ 48 cm
ECTP 25 @ 50 cm
Photo 1: Humpy Peak
Photo 2: Close up of Humpy Peak rider-triggered avalanche
Photo 3: Weakening Surface Snow
Video
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Considerable
Coordinates