Avalanche

Mt. Judah

Andy AndersonCentral Sierra Nevada
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Quick report

Calm winds and sunny skies provided a welcome respite from the wet and windy weather of the past few days. Fresh snow also helped smooth the snow surface and cover the firm rain crusts. Below 7600 ft, about 3 to 4 inches of new snow had accumulated. New snow depth increased above 7600 ft. By 8000 ft, we saw as much as 8 inches of new snow. This dense new snow seems to have bonded well to the rain crust below and to itself. Below the rain crust, several feet of wet snow still existed.

Our ski cuts, kicks, cornice drops, and snowpit tests did not produce unstable results on wind-loaded test slopes. We ran into several other parties who had similar observations. One group reported that one of their tests produced a sudden collapse at the end of the loading steps. We saw one small wind slab avalanche that looked like it happened during the storm yesterday, but tests near it also did not produce signs of instability today. 

While evidence of current lingering instability was hard to find, it was easy to see signs of yesterday's gale-force winds. The SW winds scoured the upwind sides of ridges and other terrain features back to the rain crust. We also saw numerous ripples and other wind textures on the snow surface. Most exposed slopes had some wind effects, including wind-packed snow in loaded areas. Sheltered terrain held softer, more consistent snow surfaces. 

We saw on D1.5 avalanche that likely occurred yesterday.

Weather

Air Temp
30 °F
Cloud Cover
clear
Wind Loading
previous
Recent Snowfall
5 to 20 cm
Snow Avail For Transport
small smounts

Calm winds, and sunny skies above 7800 ft. Fog existed in some valleys up to 7800 ft this morning.

Avalanche

Size
D1.5
Aspect
NE
Trigger
NC
Elevation
7700 ft

This small wind slab avalanche looked like a cornice failure triggered it. New snow and wind-blown snow had mostly filled in the flanks and the crown. The debris also had some snow on it.