Western Chugach, Chugach State Park, South Fork Eagle River area
Western Chugach, Chugach State Park, upper Peters Creek area
Summary:
Where the snowpack is thin and has poor structure human triggered slabs occurred on persistent weak layers.
Surface hoar (3-8mm) exists above 4000’ on all aspects and faceted crystals have developed under a melt-freeze crust on solar aspects. These two weak layers are of concern with future loading.
The snowpack, in general, had poor structure (3-5 lemons) and high spatial variability. The melt-freeze crust on sufficiently steep solar aspects was up to 7mm thick and non-supportable (i.e. breakable).
Small collapses (“whumphs”) and cracking (up to 4m radius) were observed in areas of the snowpack with a previously wind-packed layer.
Human-triggered persistent slab, west aspect, ~4300′, ~37º slope, ~30cm thick and ~60m wide that run ~150m. Snowpack structure here was poor and the weak layer was faceted grains. Avalanche triggered by ski-cutting a convexity, which also happened to be a thin/shallow area of snowpack. Debris was slow-moving. SS-ASc-D1.5-R1-O:
Loose-dry avalanches (aka “sluffs) were human triggered on shaded aspect above ~4500′. Old wet-loose avalanches from the past five days were observed. Even older (one to two weeks ago) wind slab and persistent slab avalanches were also observed.
Snowpits:
