Close
PROFESSIONAL OBSERVATION FORM
 Start Date: 03.17.17 End Date: 03.17.17 Name: Savage Operation: SAC
 Drainage/Route:  Pioneers (Hyndman and N Fork Hyndman Ck via yurt - recreational trip) Observed Terrain:  8500-12000' Zone/Region:  Wood River Valley
WEATHER OBSERVATIONS
 HN24: HST: 10cm Sky: X Precip: Temps:
 Ridgeline Wind: Strong from the Variable
 Blowing Snow: M Snow Available for Transport: Small amounts
 Comments: Sunny Friday, OVC Sat and STR/EXT W/SW winds over 11000', 7cm snow Sat night with a tiny bit of rain at yurt, MOD/STR W/SW winds on alpine ridges Sun with mostly OBS skies and snowing PM. OVC Monday am. Light freezes each night at yurt.
AVALANCHE OBSERVATIONS
 No. Location Date Size Type Trigger Aspect Elevation Comments
 5 Hyndman Ck drainage Within past week 1.5 WL N W alpine Several D1 and a few D2, WL, on Friday, mostly on W and SW.
 10? alpine cirques Within past week 1.5 SS N NW >11000 Wind slabs in steep shady terrain, failing well below ridges, may have been hit from above in many cases. Crowns clearly visible Friday and getting partially filled in by Sunday.
SNOWPACK OBSERVATIONS
 HS:  
 Upper Pack: Near/below 8750'= wet snow, little freeze each night. 8750-9500'= damp/moist new snow, some partially frozen melt freeze below that. 9500-12000'= Dense windblown new snow, ice, some fresh wind slab...mixed bag. 
 Middle Pack: Not observed, but free water was making it down into the middle and lower pack at many locations below the yurt.  
 Lower Pack: Not observed.  
AVALANCHE PROBLEM ASSESSMENT
Avalanche Characteristics
Character/Avalanche Problem:
Wind Slab

Layer/Depth:
10-20cm

Likelihood of Triggering
Sensitivity:
Stubborn

Spatial Distribution:
Isolated
Terrain
  Primary Concern Comments: Isolated wind slabs in the terrain we traveled in, but we were looking for good skiing and not searching out wind slabs. They were more widespread and appeared larger on NW-N-NE-E near prominent terrain features over 10500'.
 
Avalanche Characteristics
Character/Avalanche Problem:
Loose Wet

Layer/Depth:
10-30cm

Likelihood of Triggering
Sensitivity:
Touchy

Spatial Distribution:
Specific
Terrain
  Problem 2 Comments: On Sunday, the storm snow got warm/wet fast, even without direct sun, below 9000' on W/SW. We could have triggered WL involving Sat night's snowfall in steep terrain from 8500-9000', but we spent the rest of the day over 9000' and sky cover increased - this could have been a transient problem Sunday?
 Comments: If you stayed off the obviously wind-loaded alpine features and avoided steep W-S-E aspects below 9500', there were no significant avalanche problems. WL problem below 9000' was most obvious on W and SW but also existed on S-SE.
STABILITY TESTS
 Stability Test Results: No formal tests performed. Just some ski cutting steep test slopes for surficial WL problem below 9000'.
SNOW STABILITY
 Snow Stability Rating for your observed area: Good Confidence: HIGH Trend:
 Comments (aspects and elevations of instability, etc): Easy to avoid any avalanche hazard by staying away from wet snow below about 9000' and avoiding wind slabs in terrain over 10500/11000'.
BOTTOM LINE
 Comments: Spring transition going on now in the Pioneers. Below 9000', it's spring. Above 10000', it's still very much winter. From 9000-10000', it's changing. Fun skiing and riding as long as you have an open mind.