Avalanche

Pole Creek Drainage

PetersonGalena Summit & Eastern Mtns
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Quick report

Several large avalanches on NW-N-NE slopes were observed that likely happened during our most recent storm. The largest avalanche was 400'-500' wide. These avalanches were all above, 9500' and in wind-loaded terrain. On shady slopes, 2' of snow is on the ground and ~3 feet near ridge tops on wind-loaded slopes. 

Weather

Air Temp
Teens and 20s
Cloud Cover
clear
Wind Loading
previous
Rain Elevation
8000
Recent Snowfall
0
Snow Avail For Transport
small smounts

Clear skies and calm-light S/SW wind along ridge top. Parking area was 14F at 10AM

Snowpack

HS: At 7500' along Pole Creek Road, snow depth started at ~10cm, increasing to 60cm by 9000'. 70-90cm on N facing, wind loaded slopes at 9600'. 

Rain line: 1-2cm rain crust below 7500'. Near 8300' this crust was thin and decomposing. Above this, no crust was found. 

Surface: Primarily a mix of DF, near surface FC, and SH. By 2:30PM, surface snow below 9500' was moist on south facing slopes, and was beginning to refreeze as the sun left the valley.

At 9600' on an N facing previously wind loaded slope, ~11cm of weak Nov snow is soft and faceted (4F, 1-2mm). With ~80cm of 1F trending to F above that (See photo). Stability tests: ECTP27 & ECTP 29 @ 11cm. Of note: there is ~10cm of 1F hard snow separating early Nov FC and the most recent series of storms & was unreactive in stability tests. 

At and below, 9600' on S-SW.: No "old" Nov snow was found and no facets near the ground.  Below 8500' snow near the ground was moist on S-SW. 

Avalanche

Size
D2 R2
Count
3
Aspect
NE
Trigger
N
Elevation
9600 ft

All significant avalanches observed were on NW-N-NE aspects. All these avalanches were above 9500' near ridge tops in alpine terrain. These avalanches ranged from ~100' to 500' wide. I saw two other small avalanches were observed on E & SE facing steep slopes near 9500'.