Observation: Girdwood

Location: Raggedtop

Date:
Observer:
Route & General Observations

Toured up to 2800′ on the east aspect of Raggedtop. Dug snowpits at 2500′ and 1500′ and found buried weak layers about a foot deep in both locations. Surprisingly, we did not get any interesting results in our snowpits on these weak layers, but with more snow on the way they are very likely to become more active and produce avalanches in the coming days.

Weather & Snow Characteristics
Please provide details to help us determine the weather and snowpack during the time this observation took place.
Weather

Mostly cloudy skies with temperatures in the high 20s and low 30s. Winds were light below 2000' but picked up to gusts of ~15mph as we got to treeline.

Snow surface

About 6-10" of soft snow on the surface in protected areas. The surface snow was still fairly soft but more compacted by winds at upper elevations. There was active snow transport due to winds above treeline.

Snowpack

We dug two snowpits, at 2500' and 1400' on NE aspects. In both pits we found weak layers about 1' (35cm) deep. In the upper elevation pit there was a weak layer of facets at this depth and down lower there were facets with a layer of very large surface hoar above it. We performed compression tests, extended column tests, and a propagation saw test (PST 75/100 END). Despite the well developed weak layers in both locations we did not get propagation in any of our tests. The weak layers failed between 15-21 taps in all tests and had a sudden collapse fracture character. As more snow load develops on top of these weak layers it is likely that they will become more reactive and produce both avalanches and propagating test results.

Photos & Video
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