Alud

Skyline Lake area

Josh HirshbergStevens Pass
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Foto de la observación 1Foto de la observación 2Foto de la observación 3Foto de la observación 4Foto de la observación 5Foto de la observación 6Foto de la observación 7Foto de la observación 8

Quick report

Cracking
specific

One notable example of cracking- a convex slope ~38° had "spider-web" cracks across it, but hadn't slid.

Weather

Cloud Cover
overcast
Wind Loading
previous
Recent Snowfall
50cm
Snow Avail For Transport
large amounts

Storm snow: HN24 30cm, 50-60cm since 1/6. There was a wind event/peak temp on the night of 1/6. 10-15cm of colder, lower-density snow fell over this by morning. Lots of new snow. S1 through mid-AM. Snowfall tapered with intermittent thinning/ lifting of clouds by late AM. Winds were calm with light gusts at 5,400ft ridge. Temperatures warmed near freezing at pass level by noon

Snowpack

The top 10-20cm of storm snow was exceptionally light (F hard) over a slightly stiffer layer from overnight. The hardness of storm snow was "right-side up" on sheltered slopes, but not in wind-exposed terrain.  The storm interfaces were stubborn to trigger on shorter and well-supported slopes. The 1/3 crust was 75-100cm below the surface at low-middle elevation wind-sheltered terrain. Generally, we saw a good bond at the 1/3 crust. However, natural and triggered (by others) avalanches indicate otherwise.


A quick profile of storm snow on a slightly wind-loaded 5,450ft ridge:
0-20cm: F+ hard
20-40cm: 4F+, moderate hand shear, planar (RP)
40-60cm: 4F

Profile (wind sheltered). S, 5,300ft
HS 206cm, boot pen 145cm, HST 50cm
↓30cm : mid-storm 1/6 interface. Sudden results CTE(SP)
↓50cm: 1/6 interface. resistant planar  results CTM(RP)
↓76cm: 1/3 crust. Broken results CTM(BRK)
See profile photo and graph

Avalanche

Size
D2.5
Type
HS
Count
3
Aspect
SE
Trigger
NC
Elevation
6600 ft

Natural cycle of D2 soft slabs in wind-sheltered terrain overnight. Loose dry avalanches 10-15cm deep were stubborn on most slopes, but easy to trigger on unsupported or sustained +40° slopes. Evidence of 2-3 slab avalanches (all lee/cross-loaded) that likely ran in old snow layers, 1/3 crust or deeper. One impressive, very large hard slab avalanche on Rock Mtn.