Island Park

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. 

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.

We saw a small natural avalanche below Reas Peak on a northerly aspect. Photo: GNFAC

We saw two avalanches below Reas Peak on North aspects that were likely triggered by snowmobilers. Photo: GNFAC

We saw two recent natural avalanches that broke below the wind-drifted snow in Jefferson Bowl. Photo: GNFAC

We saw two recent natural avalanches that broke below the wind-drifted snow in Jefferson Bowl. Photo: GNFAC

We saw a natural avalanche that broke near Yale Creek on a southern aspect that broke below the recent snow. Photo: GNFAC

Rode up to maintenance shack then across to East Hotel creek and dug on the south slopes. 
From there we rode to upper Hellroaring creek and to below Reas peak and dug another pit. Then we traveled up and around into Jefferson bowl before heading out.

Avalanche activity seen: 5 total

2 appeared to be rider triggered near Reas peak on North aspects that broke within or just below the new storm snow. (D1/D2)

We saw a natural avalanche that broke near Yale creek on a southern aspect, again broke below new snow. (D1)

2 large natural avalanches that broke within the wind drifted snow in Jefferson Bowl.(D2/D2)

Snow depth ranged between 225-275cm in our test pits.

No signs of instability seen on our ride but temperatures were increasing and wet snow activity will likely follow. In our pit above East Hotel we observed the new snow to be bonding well with the old.  (ECTN’s 15/17)

In Hellroaring below Reas we observed facets above and below the upper most crust under the new snow and got propagation.(ECTP15)

Travel Advice: 

Human triggered avalanches are still possible but it is not unreasonable to explore into avalanche terrain.
However, we suggest digging down about 3’ below the new snow and asses how it is bonding before riding into steeper terrain. As always carry rescue equipment and reduce risks by only exposing one person at a time while others keep watch from non-avalanche terrain.