Join us at our 2nd Annual Blizzard Ball

Observation: Yellow Jacket

Observation Date
1/6/2025
Observer Name
Champion & Gagne
Region
Salt Lake » Mill Creek Canyon » Yellow Jacket
Location Name or Route
Yellow Jacket Trees
Weather
Sky
Overcast
Precipitation
Light Snowfall
Wind Direction
Northwest
Wind Speed
Light
Weather Comments
Kind of a stormy day—overcast with consistent cloud cover throughout. Visibility came and went, with periods of precipitation. Probably about 1-2 inches of fresh snow piling up on the brims of our hats and along the uphill skin track on the way out. Temperatures remained cool throughout the day, and felt as though they dropped by the end of the tour.
Snow Characteristics
New Snow Depth
3"
New Snow Density
Low
Snow Surface Conditions
Powder
Rain-Rime Crust
Snow Characteristics Comments
Probably about 3 inches of new snow in the last 24 hours. Which was very soft low density snow. Beneath that, there's around 12 inches of fresh, soft snow across nearly all aspects. Pretty impressive riming on the trees and much of the snow surface.
Red Flags
Red Flags
Recent Avalanches
Poor Snowpack Structure
Red Flags Comments
Basically all the red flags have been checked over the past few days. Today, the two that stood out most were the recent avalanche activity in the Yellow Jacket Tree drainage and higher up on the ridgeline, along with the overwhelmingly poor snowpack structure. We dug in multiple zones on the northern aspects, and in each one, we found an impressively weak snowpack—all with some kind of slab sitting on top of weak, faceted snow.
Avalanche Problem #1
Problem
Persistent Weak Layer
Problem #1 Comments
The persistent weak layer remains pretty straightforward.
Similar to Trent’s observations in Mineral Fork yesterday, below about 8,000 feet, the "Christmas" warm-up was very evident. This crust—whether temperature- or rime-induced—had a bit of soft snow above it, making travel relatively comfortable below 8,000 feet due to the rime layer and general coverage. Below this elevation, the terrain remained pretty shrubby.
Above 8,000 feet, in the mid and upper elevations, we found well-developed and obvious facets on most north-facing terrain. We dug in two primary locations: one with a shallower snowpack measuring 65 cm and another with nearly double the depth at 124 cm. In both pits, the bottom half of the snowpack consisted of facets. The primary difference between the two snowpits, aside from overall depth, was the degree of wind-loading and the hardness of the slab above the weak, faceted snow.
In the shallower snowpit, located on a west-northwest aspect at 9,300 feet, the slab appeared to have been slightly wind-scoured. The snow overlying the facets ranged from fist hard to four-finger hard.
In the deeper snowpit, on a northwest aspect at 9,350 feet, the upper 30 cm of the snowpack was fist hard to four-finger hard, while the middle 25 cm, directly above the facets, was 1F hard. Despite the differences in slab characteristics, the weak layer was very apparent in both locations. Although our tests didn’t result in propagation, the snowpack structure remains simple and concerning. I still wouldn’t trust it and would avoid traveling into avalanche terrain.
We also observed two recently triggered avalanches. We inspected the upper crown, located at 9,500 feet on a northwest aspect, on a 36-degree slope with steeper sections along the ridgeline. This avalanche failed as a solid 1F-hard slab sitting atop F-hard facets, underscoring the danger of the persistent weak layer.
While the likelihood of triggering an avalanche on this layer may gradually decrease and visible signs of instability might become less obvious, the consequences of triggering one remain just as deadly.
Photo of the crownline/starting zone at 9500' on a NW aspect.
Photo of the 1 Finger Slab sitting atop of facets in the starting zone - 9500' - NW aspect
Additional photo of the avalanche that ran from 9500-8400'. We found the lower debris in the trees.
Photo of the lower avalanche debris that had been reported 1/4 near 8200'.
Today's Observed Danger Rating
None
Tomorrows Estimated Danger Rating
None
Coordinates