On Henderson Bench we saw 2 new avalanches that looked fresh, possibly cornice triggered. It was not windy, so windloading was not the trigger. Regardless, it was disconcerting. Photo: GNFAC
A 70 cm wind slab broke on the facets in our stability test (ECTP 21) and also in the avalanche. Photo: GNFAC
We rode to the cabins in Fisher Creek and skied up Wades World. A slide from last week was visible and we dug a few hundred feet above it. Photo: GNFAC
We rode to the cabins in Fisher Creek and skied up Wades World. A slide from last week was visible and we dug a few hundred feet above it. A 70 cm wind slab broke on the facets in our stability test and also in the avalanche. We got 2 large collapses as we approached the crown of the slide and another an hour later near Henderson Mtn. On Henderson Bench we could see 2 new avalanches that looked fresh, possibly cornice triggered. It was not windy, so windloading was not the trigger. Regardless, it was disconcerting. Across the Fisher Creek valley we could see a slide on the nose of Sheep Mountain on the same slope that killed a snowmobiler in 2015.
Whumpfs yesterday and today, recent slides, and a poor snow structure is worrisome.
Heavy and wet snow from the top of the ridge down to the Bridger Bowl lot. Observed large pinwheels, old avy debris on 30 degree slopes. 2 finger facets 15cm down, depth hoar still intact and showed no signs of rounding. Shooting cracks underfoot while skinning.
South of two top north west of trail intersection #20. (saturday 1/27)
rode low angle stuff all day, creek bottom is normally not visible and its down to dirt. The whole area (south of two top) seemed really shallow and west facing slopes were very windswept when exposed, but filled in down low.
We found that the weak layers are all over the place after the warm weather and rain. Super faceted snowpack everywhere we went and even in low angle trees you could stick your hand in next to where a snowmobile track was and break a slab off. When rolling sleds over on a small hill we broke off lots of big 3' x 3' chunks down to the old really deep weak layer.
We did not see any avalanches.
Skied and dug in the trees W of Bradley Meadows at 7690’. Ski quality was terrible as the upper 20cm was becoming very heavy and wet, even on this NW aspect, in the trees. It was 48 degrees air temp at 2pm.
Dug two pits, each with slightly different aspects, and got mixed results just 25’ away:
NW: ECTP25 down 55 on 2mm facets, ECTX x 1, HS of 85.
W: ECTP26 down 67 on 2mm facets, ECTX x 2, HS of 97.
No other signs of instability, and there were quite a few skiers out, none of whom mentioned anything other than the poor ski quality.
Numerous collapses in any terrain with a non-wind effected snowpack over 70 cm. Recent warm weather leading to settlement of the upper pack and a much denser slab. 3x natural size 1 natural wet loose off palace butte in steep rocky terrain, which happened before noon. Below 8000 feet the snowpack was moist to the ground in the pm.
<p>Dangerous avalanche conditions continue across the advisory area due to an incredibly flimsy snowpack structure with persistent weak layers of feathery surface hoar, sugary facets and depth hoar buried 1-3+ feet deep.</p>
<p>Can we get one day without avalanches? Apparently, this is still too much to ask for. Yesterday, a group of skiers in the Bridger Range kicked off a microwave-sized chunk of cornice that tumbled down and triggered an avalanche on Bridger Peak (<a href="https://www.mtavalanche.com/node/30347"><strong><span>video and details</span></strong></a>). A snowmobiler was researching a new stability test we’re calling the cannonball and triggered a small avalanche on a test slope in Lionhead (<a href="https://www.mtavalanche.com/node/30350"><strong><span>video and details</span></strong></a>). Doug described conditions in Cooke City as spooky, triggering thunderous collapses (<a href="https://www.youtube.com/watch?v=BPzHM3837QY"><strong><span>video</span>…;). Similarly, groups in the Southern Gallatin and Southern Madison Ranges triggered many collapses wherever there was a hint of wind-drifted snow on top of the weak layers (<a href="https://www.mtavalanche.com/node/30343"><strong><span>observation 1</span></strong></a><strong> </strong>and<strong> </strong><a href="https://www.mtavalanche.com/node/30344"><strong><span>2</span></strong>…;). In Island Park, I felt my sled drop as we triggered a collapse in low-angle terrain and repeatedly found unstable conditions in our snowpits (<a href="https://www.youtube.com/watch?v=zkNFeC4omls"><strong><span>video</span>…;). Reaching back to last week when avalanche warnings and high danger were the norm, the <a href="https://www.mtavalanche.com/weather/wx-avalanche-log"><strong><span>wea… and avalanche log</span></strong></a> is packed with documentation of recent slides.</p>
<p>When persistent weak layers are a problem, careful route selection is essential to enjoying a safe day in the mountains. Recreate in terrain less than 30 degrees and reduce time spent below steep slopes. (<a href="https://www.youtube.com/watch?v=_d5_vlY-bjg"><strong><span>Slope Angles and Avalanche Terrain Video</span></strong></a>).</p>
<p>Temperatures remained above freezing in the Bridger Range last night and barely dropped below in other areas. A moist snow surface and pinwheels are early indicators of increasing wet snow instability. Shady north-facing aspects will likely remain protected from this hazard. Roofs with snow are prone to avalanches as temperatures warm. Avoid spending time below snowy roofs and keep kids and pets away from the impact zone.</p>
<p>Human-triggered avalanches are likely, and the danger is CONSIDERABLE.</p>
<p><span>Thanks to all of you who submitted photos and observations of avalanche activity. It is incredibly helpful for the accuracy of the forecast!</span></p>
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar.
Every weekend in Cooke City: Friday at The Antlers at 7 p.m., Free Avalanche Awareness and Current Conditions talk, and Saturday from 10 a.m.-2 p.m. at Round Lake Warming Hut, Free Rescue Practice.
