Wind slabs on Heavens Peak

Location Name: 
Forecaster Observation - Heavens Peak, GNP
Region: 
Outside of the Advisory Area
Date and time of avalanche (best estimate if unknown): 
Sun, 04/16/2017 - 14:30
Location Map: 


Red Flags: 
Recent avalanche activity
Rapid warming
Obvious avalanche path

Observation made by: Forecaster
Avalanche Observations
Avalanche Type: 
Dry
Slab
Slope: 
40degrees
Trigger type: 
Skier
Crown Height: 
1 ft
Aspect: 
Northeast
Avalanche Width: 
600ft.
Terrain: 
Above Treeline
Elevation: 
8 700ft.
Avalanche Length: 
1 900ft.
Number of similar avalanches: 
3
Number of people caught: 
0
More detailed information about the avalanche: 
  • Dozens of wet loose avalanches on  east through south through west aspects at higher elevations that ran through the day, such as on Garden Wall, small to large in size. ~20x LW-N-R1-D1/2-I
  • One relatively small wind slab that looks like it ran naturally yesterday on a N aspect at 8,000 ft on Heavens.  SS-N-R1-D1.5-U  (Photo 1)
  • One large slab avalanche that ran mid-day on the southeast face of Heavens at 8,500 ft.  About 500 feet wide on a windloaded slope. May have been triggered by a wet loose avalanche. Looks like it ran on the storm interface. SS-N-R2-D2-I  (Photo 2)
  • On a northeast aspect at 8,700 ft, I was stomping near a wind-loaded ridgeline, and I triggered a large slab avalanche that was surprisingly wide (about 600 feet and wrapped into a second terrain feature), 8-18" thick and ran about 2000 vertical feet.  Given the large terrain, the slide was easily large enough to bury someone and could have snapped some small trees.  It broke on small-grained facets above the most recent crust.  SS-ASc-R2-D2.5-I.  (Photos 3-5)

Above about 7,000 feet, there was 6-18" of new snow, depending on wind affect, over the most recent crust layer.  The new snow wasn't barking with signs of instability apart from the avalanche activity noted above.  On a wind-loaded rollever at 8,000 feet, I got ECTNH results at the crusty storm interface 15" down.  Minimal cracking observed through the day.  Surfaces got wet on all but northerly aspects.  Below 6,000 feet, there was minimal new snow and apparently low hazard where we traveled.   Surfaces became wet but remained supportive through the day.  

Avalanche Photos: 
Weather Observations
Cloud Cover: 
25% of the sky covered by clouds
Air temperature: 
Above Freezing
Wind Speed: 
Calm (No air motion)
Precipitation: 
None
Air temperature trend: 
Warming
Activity: 
Skiing