Avalanche

Avalanche: Talking Mt. Cirque

TrenbeathMoab
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Avalanche

Slab Width
152 m
Weak Layer
Facets
Trigger Type
Natural
Vertical Fall
152 m
Avalanche Type
Hard Slab
Trigger Detail
Repeater
Start Zone Aspect
East
Avalanche Problem
Persistent Weak Layer
Start Zone Elevation
3475 m

This avalanche occurred mid-storm cycle that ran from March 13-17. It likely occurred sometime between March 15-16 when 12" - 15" of new snow had fallen accompanied by a period of strong and sustained, SE-NE winds. This was the first major storm event in over a month. The cycle ended on March 17 with 21" of total snowfall at 2.4" SWE. On Sunday, March 17, numerous natural wind slab avalanches 1'-2' deep were observed on N-NE aspects near and above treeline, but this avalanche appeared to be a day or so older and had been filled back in. At first glance it appeared to be just features associated with wind drifted snow. Closer observation on March 18 revealed that it was likely a large persistent slab avalanche that failed on basal facets. This is a repeat running avalanche that first ran on Feb 3, (see report here). This recent avalanche, however, appears to have exceeded the boundaries of the earlier slide.