Avalanche on Mini Halls Chute - Angora Peak Area

Location Name: 
Mini Halls Chute - Indian Cliff Chutes
Region: 
Echo Summit Area
Date and time of avalanche (best estimate if unknown): 
Sat, 03/06/2010 - 13:30
Location Map: 
United States
38° 51' 52.9452" N, 120° 4' 34.4352" W
US


Red Flags: 
Recent loading by new snow, wind, or rain
Obvious avalanche path
Terrain Trap

Observation made by: Public
Avalanche Observations
Avalanche Type: 
dry,slab,
Slope: 
40degrees
Trigger type: 
Skier
Crown Height: 
2 ft
Aspect: 
West
Avalanche Width: 
40ft.
Terrain: 
Above Treeline
Elevation: 
8 300ft.
Avalanche Length: 
1 000ft.
Number of people caught: 
1
Number of partial burials: 
1
More detailed information about the avalanche: 

Me and my partner skied Halls of the Gods Chute on 3/6/10.  We approached from Wintoon Road, up the ridge line between Echo Bowl and Angora Bowl and skinned the Angora Bowl ridge to the top of Halls.  Upon reaching the top, another party of 4 (one of which that was the eventual triggering party) were finishing climbing one of the Chutes (as they had approached from Falling Leaf Lake).  On our approach up the Echo/Angora ridge line, we encountered a number of aspects and through information tests (pole probes, hand shears, etc...), we did not encounter any instability.  It is worth noting that the N-Aspects of Echo Summit have very large (10 ft+) cornices.

The party of 4 descended the Main Halls Chutes (splitting 2 into the skiers left, one in skiers middle and one in skiers right).  We watched their descents and did not see any instabilities other than surface sluffs.  After they exited the chutes, my partner and I individually descended the middle chute (with my partner cutting over to the skier's right chute 1/2 way down).  During both of our descents, neither of us found any instabilities.  There was evidence towards the bottom of an earlier slide (probably naturally from the storm on Wednesday).

On our ski down the apron, we watched the original party of 4 skinning back up to Mini Halls to eventually summit and ski the line again.  After a 15 minute break, my partner and I headed away from Halls (westerly) to break trail to skin up and around the backside of Angora Bowl (with our intention to ski Angora Bowl back down towards are car).

After about 30 minutes of skinning, my partner yelled that we could see a slide triggered in Mini Halls Chute.  We were relatively far away at this point, but my partner noted the slide spanned the entire width of the chute and it appeared someone was caught.  At this time, I was behind rocks and could not witness the slide.  My partner noted that the slide appeared to exit the Chute with a lot of force, disappear someone on the bench 1/2 way down, and then come over the bench down to the main apron.  He witnessed one skier on the apron out-skiing the slide debris.  He also noted that he thought the original party that triggered the slide may have skied out of the way towards lookers right.

We paused and noted that it appeared 2 persons were up above the bench and ski-zagging (which at our distance appeared to be a companion rescue).  We saw a third (the skier that had out-skied the debris) starting to skin up the apron.  We yelled "Is everyone OK" and received a response of "I don't know."  [Post-script:  the person yelling was the party at the bottom skinning up who did not have a view with the parties at the top).

We immediately headed back towards Halls to see if we could assist.  Upon arrival, we could only see the same individual skinning up towards the edge of the bench.  There was clearly 3 slide debris piles that had been split from some rocks at the top.  The lookers left and middle (from the apron looking up at Halls) were relatively small, but the lookers right was rather large.  After yelling again to see if anyone was buried, after a pause we heard a happy yell and she noted that everything was OK.  

At this point we decided to stay, called off skiing Angora face and skinned up to inspect the largest debris pile.  At the bottom, it was around 2 feet deep of debris, but I was able to push my pole through it almost up to the handle.   It did not appear to be debris from a hard-slab as it was somewhat soft.  With that said, it was compacted very tight.  Ski/skins on untracked snow next to the debris had about a shin-high penetration.  On the actual debris, there was zero  penetration  for skis/skins - as you would remain on top.

We yelled up again to find out that the triggering person was missing a ski and other gear.  We began to skin up the debris pile and were able to find hat and goggles, each several hundred yards from the bench (which was also several hundred yards from the triggering point.

Ultimately, the group of 4 came down by us and we spoke with the triggering party.  The first 3 skiers skied Mini Halls with no instabilities.  From what I understand speaking with one of the skiers, the first 3 were somewhat directly below the Chute when the slide happened.   Therefore, they scattered (and in particular, the party we saw racing down the apron indicated she was in the fall line and turned down-hill).

When speaking with the actual triggering party, he noted that he had skied several turns, and then headed over by the rock wall to get better snow (possible thinner snow pack, triggering point?).  He indicated that he witnessed the snow break around and below him (and it had also broke back behind him).  He was hit by the snow behind him with strong force.  He indicated he was fully buried throughout the course of the slide until the very end where he came to rest by the edge of the bench.  At this point, he noted he arose to the surface.  He indicated to me that he believed the crown was around 2 feet.

From our vantage point, it appeared the remainder of the debris continued on, broken into 3 routes by rocks/cliffs at the edge of the bench.

I am glad everything worked out OK for their group.  I hope they will submit the first hand observations, as we witnessed the slide from quite far away, but were the first at the bottom (of non-involved parties) to look into the debris pile.  It is also worth noting that another party of skiers/split-borders were working their way up about 45 minutes after the slide to go ski Echo.  They may have possibly inspected the crown or can verify the size.

We headed out towards Falling Leaf Lake, but since our car was at Wintoon - well.... that sucked.  At least we could help.

 

Avalanche Photos: 
Weather Observations
Blowing Snow: 
No
Cloud Cover: 
75% of the sky covered by clouds
Air temperature: 
Above Freezing
Wind Speed: 
Light
Precipitation: 
Snow
Air temperature trend: 
Cooling
Wind Direction: 
East
Accumulation rate: 
Less than 1 in. per hour
More detailed information about the weather: 

As forecasted, scattered snow showers were moving into the area.  Little to no accumulation.  From the time of the slide until approximately 4:30 PM, a number of light snow showers would pass through (on and off).  Temperatures dropped slightly throughout the afternoon.