Observation: Porter Fork

Observation Date
01/28/2018
Observer Name
Greg Gagne and Tom Flaherty

Region:

Location Name or Route
Porter Fork
Weather
Sky
Overcast
Wind Direction
Northwest
Weather Comments
Quite warm and humid. Only the cool, damp winds at the upper elevations made things comfortable.
Snow Characteristics
Snow Surface Conditions
Rain-Rime Crust
Snow Characteristics Comments

Below about 8500' snow surface was damp at 8 am on all aspects from warmth and overnight cloud cover.  Above 8500' 1-2 mm rime crust on windward (northwest/west) aspects.

Surprisingly decent coverage in Main Porter with 1 - 1.5 meters above 8000'

Shallow ski pens with decent, supportable travel conditions.

Red Flags
Red Flags
Poor Snowpack Structure
Comments

First visit to Porter Fork in Millcreek this season. Was pleasantly surprised with the depth of the snowpack given much of this terrain is low to mid elevation. The primarily northerly aspect has likely helped preserve whatever snow has fallen this season. 

There have been a couple of persistent slab avalanches so far this season in Porter Fork:

- Icebox (Main Porter)

- In Between (Main & West Porter)

and I was expecting to find a poor structure.

Several quick pits, as well as two pit profiles. Most were showing HS 1 - 1.5 m. Stability tests were ECTX or ECTN.

 

Pit profile of NW aspect at 8500

 

This pit on a NW aspect at 9500'  was modestly decent, with faceted layers showing signs of rounding likely due to the deeper snowpack. Probably the best snowpack structure I've seen this year (but then again, this wasn't great, and the other 100+ pits have looked awful.)

Frustrating to see the warmth, but this can only help minimize faceting and hopefully slowly help the snowpack gain strength.

Traveled in Days Fork on Saturday (no observation) and Porter Fork this Sunday. Looked at quite a bit of snow. All stability tests were ECTX or ECTN (no propagation.) Quite a bit of spatial variability within the poor structure ranging from a 4F/1F slab on top of the facets, to a 4F- slab deteriorating slab in thinner areas.

Am thinking it will get increasingly difficult to trigger a persistent slab avalanche, but the poor structure and significant consequences will keep me off of steep north -> east terrain for the time being.

Photos of rime crust as well as cloud layer.

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