Observation: Public
Observation Details
Name:
Dan BolligerObservation Date:
April 10, 2022Submitted:
April 11, 2022Zone or Region:
Snoqualmie PassActivity:
Skiing/SnowboardingLocation:
Rampart RidgeTriggered Avalanches
Did you trigger any avalanches?
YesWas it intentional?
NoAvalanche Type:
Soft SlabSize:
Size 1: Relatively harmless to peopleElevation:
4500Aspect:
SEComments:
D1 soft slabs were easily triggered on steep slopes on all aspects - particularly on convex rollovers and in gullies. These soft slabs had a defined crown anywhere between 4-12". Generally, in the trees on windward NW slopes they were shallower, with the deepest crows on open, leeward SE slopes. These small slides never propagated more than 12-18" past the tips of our skis, quickly arrested themselves on slopes less than ~30 deg, and did not fan out much relative to the width of the trigger. In a few extra steep SE gullies the bed surface was a hard supportable crust which made skiing more challenging, while elsewhere it was some sort of soft mid-storm layer (did not appear to be groupel).Signs of Unstable Snow
Observations
Our party toured the southern terminus of Rampart ridge. We generally skied SE aspects from 4-5k and found deep, light powder and minimal winds. The only time that the wind really picked up was on an exposed ridgeline around 5400' where there were large amounts of blowing snow. Throughout the day, it snowed moderately with one partial sun break around 4pm, which didn't seem to have a major impact to the snow surface on SE aspects. On our final exit run down a steep West slope, we found heavier saturated snow below 4k and the soft slabs we had encountered earlier subsided. Comparing coverage in this zone to the start of 2023, we found similar conditions however some creeks were more exposed with running water, and steep S aspects had thin spots where the snow had been scraped to dirt. On a ridgeline at 4900', HS was 240cm. The soft slab avalanche activity was straightforward to manage - the group kept eyes on eachother and skied every run in pitches, moving to safe zones and and skiing ahead/behind the flowing snow. In our opinion, the main concern of the day was burial in a tree well and thus we maintained visual contact with eachother throughout the day.
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