We rode from the Buttermilk trailhead up Denny Creek to Lionhead Ridge, along Lionhead Ridge through Watkins Creek and to the motorized boundary at the head of Targhee Creek.
There was a ~1" crust at the surface when we left the trailhead, with dry snow beneath. We saw our first wet loose avalanche of the day running around 11 am. By 12:30 there were dozens and many rollerballs. None of them ran particularly far or picked up too much volume. The snow surface was moist on sunny slopes by late morning, but not more than a few inches down.
We toured down the west side of the Bridger Range on the edge of Truman Gulch and found predictably weak snow on an upper-elevation NW-facing slope. Conditions were variable and transitioned to a thick crust as we moved on to a lower elevation, west-facing slope. By the time we came down the Ramp, the snow was getting wet, we saw roller balls, and we avoided steep, sun-exposed terrain.
We dug below NW Passage. It was a 135 cm deep snowpack, dry throughout, with Fist plus hard facets and depth hoar making up the foundation (ECTP30, PST 42/100 end at 30 cm from the ground.
We rode from the Buttermilk trailhead up Denny Creek to Lionhead Ridge, along Lionhead Ridge through Watkins Creek and to the motorized boundary at the head of Targhee Creek.
We saw one small slab avalanche that occurred since this weekend's snow. It appears to have been triggered by a snowmobile yesterday (4/1/24). It broke 10" to 2 ft deep, 50 ft wide, and ran ~50 vertical feet. It broke on a thin layer of facets beneath the new snow. Digging in the crown, dry facets at the ground were along still present and weak (fist hardness).
We rode from the Buttermilk trailhead up Denny Creek to Lionhead Ridge, along Lionhead Ridge through Watkins Creek and to the motorized boundary at the head of Targhee Creek.
There was a ~1" crust at the surface when we left the trailhead, with dry snow beneath. We saw our first wet loose avalanche of the day running around 11 am. By 12:30 there were dozens and many rollerballs. None of them ran particularly far or picked up too much volume. The snow surface was moist on sunny slopes by late morning, but not more than a few inches down.
We rode from the Buttermilk trailhead up Denny Creek to Lionhead Ridge, along Lionhead Ridge through Watkins Creek and to the motorized boundary at the head of Targhee Creek.
There was a ~1" crust at the surface when we left the trailhead, with dry snow beneath. We saw our first wet loose avalanche of the day running around 11 am. By 12:30 there were dozens and many rollerballs. None of them ran particularly far or picked up too much volume. The snow surface was moist on sunny slopes by late morning, but not more than a few inches down.
We saw one small slab avalanche that occurred since this weekend's snow. It appears to have been triggered by a snowmobile yesterday (4/1/24). It broke 10" to 2 ft deep, 50 ft wide, and ran ~50 vertical feet. It broke on a thin layer of facets beneath the new snow. Digging in the crown, dry facets at the ground were along still present and weak (fist hardness).
Signs of older avalanches were visible beneath the new snow, including one slide that broke in early March. No cracking or collapsing were observed today.
Saw no signs of instability. Skied east to southeast aspect slopes. The snow did get moist, but not sloppy, in the afternoon. Did not execute any snow pits and accompanying test. The snow pack felt solid. Would have been nice to do a little snow science, but it was a long tour.
<p><span><span><span>Conditions change rapidly in the spring, and travel plans should reflect these daily fluctuations. While not equal in likelihood, wet snow avalanches, dry slab avalanches failing in the upper snowpack and deep slab avalanches failing on basal weak layers are all potential problems today. </span></span></span></p>
<p><span><span><span>Natural and human-triggered wet snow slides will become likely as the spring sun blazes and temperatures rise into the 40s and 50s F. These will generally present as wet loose avalanches that start at a point and fan out as they entrain snow. The weight of these slides pack a serious punch. Yesterday, the Big Sky and Bridger Bowl Ski Patrols observed limited wet snow instability when small natural avalanches occurred in closed terrain. We will likely see more today. Wet snow instability is rising as the surface snow gets wet (duh!) and pinwheels of snow start rolling downhill like giant cinnamon rolls. Quickly move to cooler aspects, lower-angle slopes or head home as instability increases, and preemptively ensure a safe exit plan.</span></span></span></p>
<p><span><span><span>The avalanche danger is MODERATE this morning and will rise to CONSIDERABLE as wet snow avalanches become likely. </span></span></span></p>
Hyalite Road Closure: Hyalite road is closed to ALL MOTORIZED VEHICLES until the morning of May 16. This is a regular annual road closure to reduce road damage during the spring thaw. Bicycle and foot traffic are allowed. Contact the Bozeman FS Ranger District for more info.
