Observation: Maple Hollow

Observation Date
02/26/2017
Observer Name
Toddeo

Region:

Location Name or Route
Pahvants - Maple Hollow
Weather
Sky
Few
Wind Direction
Southwest
Wind Speed
Moderate
Weather Comments
Winds picked up after noon. Transport at the ridge tops and occasional transport in other areas.
Snow Characteristics
New Snow Depth
14"
New Snow Density
Medium
Snow Surface Conditions
Powder
Damp
Snow Characteristics Comments

HST = 14" above 8,500' sitting on top of a firm snow surface.  Graupel at the base.  Snow is starting to facet throughout.  East aspects in wind sheltered areas up to 8,500' got a bit damp.  Low elevation was damp in sunny areas skiing out the Maple Hollow road this afternoon.

Some surface hoar.

 

 

Red Flags
Red Flags
Wind Loading
Red Flags Comments
Potential wind loading if the winds pick up tonight. Other than that, no real red flags observed. Some potential tension cracks in the storm snow were observed on steep rollovers in lower elevation areas. Some minor sluffing of the storm snow on slopes approaching 40 degrees, minor.
Avalanche Problem #1
Type
Storm Slab
Trend
Same
Problem #1 Comments

The storm slab is sitting on a firm base with inconsistent/variable bonding.  Column shear tests were variable and ranged from Q1/2 to Q3 and moderate to hard force required to initiate via hand shears.

Avalanche Problem #2
Type
Wind Slab
Trend
Increasing Danger
Problem #2 Comments

Winds slabs could be an issue if the loading continues, not much of an issue today.

Snow Profile
Aspect
Northeast
Elevation
9100
Slope Angle
30
Comments

HS = 48", HST = 14" at this location sitting on a supportable, knife hard crust.  Glove is sitting on a layer of graupel overlying the crust.  This column sheared with a relatively clean Q 1/2.  upon close inspection (photos below) the grapuel is recrystallized and the upper plane of the shear has some faceted snow.

 

Photos below:

1. Upper surface of shear with facets.

2. Basal graupel.

3. Graupel and facets from upper surface.

Results of ECTN (new snow only), part of the column collapsed without propagation.

 

Photo below, no outing in the Pahvants is complete without some bushwacking,

Overall, I feel the hazard is a bit tricky.  I saw no major signs of instability but do not completely trust the HST/crust interface.  I did not ski my planned final run which contains sustained slopes of 40 degrees and may have been subject to some wind loading.

Generally a moderate hazard limited to storm snow.

Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Moderate
Snow Profile Coordinates