Avalanche

Purple Ridge

Eric MurrowGunnison
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Observation photo 1Observation photo 2Observation photo 3

Quick report

Cracking
isolated

Up to 10 inches of storm snow on sheltered slopes largely posed a loose snow avalanche threat, but there could be a few isolated places with sensitive buried Surface Hoar capable of producing soft slabs.  Drifted terrain features seemed like an easy place to trigger an avalanche in the recent storm snow.  Fabulous skiing!  

On drifted test slopes it was easy to trigger a soft slab in the storm snow. We did not experience any collapses an weak layers beneath the storm snow. Loose Dry avalanches were likely on slopes near or above 40 degrees in steepness.

Weather

Cloud Cover
overcast
Wind Loading
light
Recent Snowfall
25

Up to 10 inches storm snow near treeline. West to northwest winds transported some snow overnight forming very soft drifts up to 30" deep in lee places at upper elevations. Periodic light snowfall during the day amounted to an inch or less.

Snowpack

Up to 10 inches of new storm snow.  Evidence of drifting from west to northwest winds near and above treeline with more snow available to transport if winds increase.  In a few locations on shaded slopes below treeline we found small Surface Hoar (5mm) beneath the storm snow, but did not experience any cracking in the new snow.  

We dug a quick test pit on a northeast-facing slope just over 11,000 feet with 140cm depth (4.5 feet).  This lower-angled feature had a full snowpack depth (no previous avalanche activity) and seemed to be lightly drifted this winter.  No obvious buried Surface Hoar and basal facets were 4-finger+ hard.

Avalanche

Size
D1 R1
Count
3
Aspect
E
Trigger
AS
Elevation
11400 ft

While snowmobiling out the Slate River drainage, we observed a handful of small natural loose avalanches along Schuylkill Ridge. A couple of soft slabs on the south side of Cinnamon and east side of Purple Ridge in wind drifted areas. Sheltered terrain near or over 40 degrees appeared to lack a slab and pose a Loose Dry problem and wind-drifted areas presented a slab avalanche problem. Avalanches on well-drifted terrain could become large on longer slopes or places with a big fetch.