Valanga

Patterson Pk

Ethan DavisSoldier & Wood River Valley Mtns
Vedi sulla mappa
Foto dell’osservazione 1Foto dell’osservazione 2Foto dell’osservazione 3Foto dell’osservazione 4Foto dell’osservazione 5

Quick report

Triggering a large avalanche remains a possibility but you'd likely need to find a very steep, previously wind-loaded slope facing NW-N-NE.

No obvious signs of instability.

Weather

Cloud Cover
clear
Wind Loading
previous
Recent Snowfall
0
Snow Avail For Transport
none

Blue skies. Very light E wind kept it feeling cool before noon.

Snowpack

Depth:
Shaded slopes ranged from 60 cm near the valley floor to 120 cm at 8,000'. 

Surfaces:
All slopes had near surface crusts of some sort with very isolated areas holding noticeable surface hoar. 

Snowpack:
On shaded slopes, pole pokes went through 2-3 crusts and interpersed weak facets on all slopes except those that were obviously wind-loaded by early Feb. storms. S and SW were bare. W was thin and generally welded to the ground. 


The skier triggered slide on Patterson on the 18th failed in a heavily wind-loaded area. Much of this wind-loading occurred on Feb 6-7th, which also caused nearby natural avalanches. The triggered slide involved the 1/31 interface and gouged to and below the 12/13 interface, which were only about 20 cm apart. I dug on a nearby representative slope. The slab thickness was 65 cm and graded F at the surface but quickly turned to 1F. Snowpack tests returned ECTP 17, 20, 31 involving both layers. 

The persistent slab problem here appears to be tightly confined to previously wind-loaded, steep start zones facing NW-N-NE. Too high, and slopes are stripped, to low or sheltered and there is no slab. 

 

Avalanche

Size
D2.5
Count
3
Aspect
NW
Trigger
N
Elevation
10000 ft

Patterson: D1 wet loose initiating from rocks and tree within the last 48 hrs. Pioneers: D1-1.5 wet loose but not widespread. No obvious activity in the core Pioneer complex. Older large slab avalanches just past Mormon Hill in the Pioneers. Smokys: Some obvious recent wet avalanches at the head of Baker Ck.