Valanga

Upper Baker Creek

Miller, DavisGalena Summit & Eastern Mtns
Vedi sulla mappa
Foto dell’osservazione 1Foto dell’osservazione 2Foto dell’osservazione 3Foto dell’osservazione 4Foto dell’osservazione 5

Quick report

Cracking
isolated
Collapsing
specific

We observed the aftermath of a widespread natural avalanche cycle that occurred during the atmospheric river event over the last 72 hours. Nearly everywhere we looked we could find natural slab avalanches. It is impressive.

In addition to a multitude of natural avalanches, we noted cracking, collapsing and unstable test results while out today. Unstable avalanche conditions are prevalent in the Baker Creek area, and we avoided avalanche terrain as well as slopes below or connected to avalanche terrain.

This observation will be updated with more information and photos tomorrow.

Observed evidence of widespread persistent slab avalanche cycle from the past 48 hours. Found shooting cracks (~20 feet) while descending in shaded mid-elevation roll-overs where the slope steepened that broke all the way to the 1/31 surface and localized cracking in thin fresh wind-loaded features along the ridgeline. We triggered two large rumbling collapses: one at 8950' on a SE aspect with a shallower snowpack made up of storm snow, a 2cm crust and very weak facets below (dug and tested - in snowpack section) and another at 7950' on a flat protected creek bottom when stepping out of skis (guessing buried SH).

Weather

Air Temp
20
Cloud Cover
few
Wind Loading
intense
Recent Snowfall
20
Snow Avail For Transport
large amounts

Strong N winds and lots of blowing snow above 9000 feet. Generally clearing skies with a brief snow flurry around 11am.

Snowpack

We found 60-100cm of settling storm snow generally sitting atop weak sugary facets or crusts. The winds were howling and actively transporting large amounts of snow at middle and upper elevations in all open areas. We also found a razor-thin crust (from a brief mid-storm warm-up) buried by a 10-20cm thick 4F-hard wind-pressed new snow on exposed ridgelines.

We dug a quick pit after triggering a large collapse to investigate the weak layer failure. Stability tests resulted in ECTP1 and ECTP11 @ 60cm below the surface on F-hard facets below a 2cm P-hard melt freeze crust and 58cm of settled and wind-pressed storm snow.

Avalanche

Size
D2
Count
15
Aspect
SE
Trigger
N
Elevation
8900 ft

We observed avalanches nearly everywhere we looked while in the field today. These were primarily observed on steep, mid and upper elevation slopes facing NW, N, NE, E, and SE. The largest avalanches were seen in heavily wind-loaded northerly alpine terrain. Additional smaller yet numerous pockets of slab avalanches were found in wind-protected, steep, mid and lower-elevation slopes with an assumed very weak faceted structure.