Quick report
- Cracking
- isolated
- Collapsing
- specific
Unfortunately, the strong wind and rain has had its way with Hatcher Pass these last few days. Scoured ridges, stiff or breakable wind slabs, and smooth lenses of snow can be easily observed from the road on nearly all aspects at mid and upper-elevations. Along with this obvious wind effect is a slew of recent avalanches both natural or human triggered. Our party ascended the Powder Pimple towards Hatch Peak to investigate one such avalanche on Hatch Common that appeared to be naturally triggered by yesterday's wind-loading. Along the way we were able to trigger a small slab on a similar Northerly aspect that indicated to us quite loudly this problem is still here and will remain reactive to skiers. You are going to have to work to find good turns amongst the icy crusts, punchy slabs, and loose facets, but the skate track looked nice.
Our presence on the ridge triggered a small but meter thick slab on a Northerly aspect at about 3800 ft, 1-3.5 ft deep, 80 ft wide, and ran about 350 vertical feet. After the avalanche, all of our group agreed we each individually expected to observe this type of instability today, even though we had not explicitly discussed it. So while there was an element of surprise to the slab's release and our proximity to the ridgeline, the overall conditions and recent avalanches made it abundantly clear that the paradigm had shifted, and we should be treading lightly. This bullseye data is exceptionally useful for Avalanche Forecasters to understand the behavior and nature of the snowpack and is why we go out in search of instabilities so you can avoid them.Weather
- Air Temp
- 25
- Cloud Cover
- few
- Wind Loading
- previous
- Snow Avail For Transport
- none
A pretty mild and calm day on our tour. The day started with temperatures around 20° at the Lodge but felt colder. Marmot was reporting temperatures in the mid to upper 20's most of the day which is what it felt like in the sun on the ridge. Winds felt calm to light from the SE, just picking up a bit at the end of the tour, but this doesn't reflect the ridgelines, as the Hatch weather station was reading sustained teen's gusting 20's most of the day. The most notable feature of the weather was the quite obvious and widespread effect recent winds had around the pass. Scoured ridges, cross loaded gullies, and smooth drifted lenses could be found on nearly every aspect at mid and upper elevations.
Snowpack
The snowpack is jacked up. Just about 3 days of very strong winds have transformed the landscape at Hatcher Pass. Previous to this storm our snowpack was mostly loose, faceted snow with an errant decomposing crust here or there, sitting on a virtually omnipresent basal ice crust from a mid-October storm. Now, we have a wind-scoured hellscape of Heather and Tundra frozen in ice, strastrugi-shredded facet pillows, and smooth, wind loaded lenses, pillows, and sculpted ribbons. But at least the basal ice is still there. The paradigm has shifted, and wind-loaded features should be suspect as they are variable in firmness or supportability and lie on a variety of surfaces including facets and crusts that increase their instability. These wind slabs are scattered in a wide and chaotic distribution with little correlation to the previous day's strong east and southeast winds.
Avalanche
- Size
- D1.5
- Type
- SS
- Count
- 2
- Aspect
- N
- Trigger
- AS
- Elevation
- 3800 ft
We triggered this avalanche on our way up the ridge to Hatch Peak to check out a natural slab avalanche that occurred 12/5. No one was caught or carried. We investigated and performed crown profiles on both avalanches.