We went to the Swan Range looking to ski a high peak. Once we got there all we could see was white. We still managed to find some small wind slabs in the fog.
We stomped on many cornices and were able to trigger 3 or 4 small wind slabs on the slopes below. These were soft, up to 6 inches thick, and were sliding on a recent crust. Layers of older slab below added up to about 3 feet thick in total. These bigger, stacked, drifts were harder and we did not get any of them to move, though we weren't interested in skiing steep slopes with that kind of hazard.
We saw no recent avalanches. We talked with another party who skied some steeper slopes than we did and they had similar results-small wind slabs sliding on a thin crust.
About that crust...We found the skinny little thing on all aspects and elevations, buried under 15 to 30 cm of newer snow. It was the bed surface for the wind slabs we triggered, and we got a propagating test result under the crust. We also found a layer of 1 cm surface hoar buried under about 45 cm. The feathers were broken and were mixed with graupel and rimed snow flakes in wind-exposed areas. They were better preserved on sheltered, northerly slopes where we could easily pull hand shear blocks from them. Though our one propagating test result failing on the surface hoar was on a wind-loaded, west-southwest aspect at 6,850 feet.
Winds were calm to light all day with light snow showers until about 1pm. Things were pretty murky, warm, and wet below 4,000 feet. And of course, the sky was clearing in the valley as we got back to our truck around 4pm.
We managed to navigate our way along the windward side of an alpine ridge and found planar, wind sheltered slopes to ski with soft, enjoyable snow and no cracking wind slabs.
Results of small (coffee table) to medium (refrigerator) cornice drops.
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