# Photos from Cameron Pass avalanche, Trap Park 1/1/06



## frenchy (Oct 10, 2003)

Yesterday 6 of us went up to check out the avalanche in Trap Park that claimed the lives of 2 snowmobilers on New Year's day. The avalanche was on a NNW facing slope ranging from 34-38 degrees in steepness at 10,800'. The crown was 140cm at it's deepest point and was roughly 200 wide and ran about 600 feet.

Here are some photos of the slide, debris pile, and our snowpits. You'll see one of the two snowmobiles that are still burried, the other one has not yet been located. The sticks planted in the debris were used as probes by the party to locate the victims.




























For more photos, go to:
http://www.powderbuzz.com/obs.php

A preliminary accident & rescue summary has been posted on CAIC web site. This will be updated over the next few days with a full report, photos, and snowpit profiles:
http://geosurvey.state.co.us/avalanche/Default.aspx?tabid=399

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Trap Park
January 1, 2006
7 snowmobilers caught, 5 partly buried, 2 buried and killed

Accident Summary
Late Sunday morning 2 snowmobilers were buried and killed in an avalanche in the Trap Park area (near Trap Lake) of the Front Range -- about 3.5 miles ENE of Cameron Pass and 4.5 miles NNW of Poudre Pass (north boundary of Rocky Mountain National Park). The area is accessed from the Cache la Poudre Canyon via the Long Draw Road. There were 12 snowmobilers in the party. Seven machiners were caught, five partly buried and two fully buried; both buried riders were killed. 

The group had ridden the slope the week before and had made multiple high marks before the avalanche. There were two riders at the top of the slope, one on the slope, and nine waiting at the bottom. Three riders at the bottom had their machines pointed downhill and were able to out run the avalanche. One man -- on the slope -- triggered the slide and he and the next rider in line to high mark were buried. Five of the nine at the bottom were overrun and partly buried.

Rescue
Some members of the group were equipped with transceviers, but at this time we are unsure of how the two buried snowmobilers were found. The first rider was found under his machine about 45 minutes after the avalanche. He had been buried about 5 feet deep. Companions also found the second machiner some time later. It sounds that both victims had been found by the time organized rescuers arrived.

We will be visiting the site on Monday and will post more information as it becomes available. 

Greene and Atkins, 1/1 at 2110.

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## jk (Dec 2, 2005)

Thanks for posting these pics. Pretty amazing to see the crown up close like that. Any ideas on the numbers of the stability tests shown in the pics? Or what layers failed? 

Made me wonder how you asess the risk of a second/subsequent avalanche when you're going back into a site that's recently slid. A variation on "let's not get killed trying to rescue someone in trouble."

Thanks again.


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## frenchy (Oct 10, 2003)

Hi jk,

We considered several factors before heading up the path. First, the avalanche broke near the top of the steep part of the path, and just above the crown the pitch relaxed in steepness considerably, meaning there was very little left that could potentitally slide. The avalanche slid to the ground, so the potential of stressing the snowpack while climbing or traversing was nil and allowed us to use the path as a safe zone. When digging our profile at the crown, we stayed below the crown and never loaded the slope above. The path to our right (skier's left) was of greater concern, and therefore exercised caution when digging into it and skiing out, again using the path that had already slid as our safe zone. This was a particularly safe avalanche site - this is not always the case. Here's a view of the path, as seen during our inital approach to the site.










We dug two full snowpit profiles so we could record snow depth and plot all layers of the snowpack with correlating temperatures, hardnesses, densities, & stability test results. Our profiles were located on the crown face and just off from the right flank in underdisturbed snow. In terms of stability tests. In our first pit we did a shear test and 2 compression tests, and in the second we did 2 compression tests. Stability tests were consistently failing in the new snow layer, a thin mid pack layer sandwiched between hard slab, and in the depth hoar layer at the base of the pack. Results varied from easy shears in the upper pack, to moderate-hard clean shears in the mid and lower pack. Our results clearly pointed to a tender snowpack that had the greatest potential to fail in the mid-pack and step down to the ground. One of our big question was, how could these slopes bear the stress of multitudes of high-mark runs before failing?

There is much to learn at avalanche sites, from poking around, to digging pits, and having discussions with peers. They are live classrooms that hold many secrets, and where knowledge and respect of nature's forces can be gained. Just always remember, when venturing into avalanche country, know your snow, never stop thinking, and choose your travel partners wisely.

My thoughts go out to the friends and families of the two deceased snowmobilers.


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## jk (Dec 2, 2005)

> Results varied from easy shears in the upper pack, to moderate-hard clean shears in the mid and lower pack. Our results clearly pointed to a tender snowpack that had the greatest potential to fail in the mid-pack and step down to the ground. One of our big question was, how could these slopes bear the stress of multitudes of high-mark runs before failing?


Thanks for the thoughtful response. Your last sentence is the $500 question and one that lures many BC sliders into trouble. Frequent reports suggest that any number of runs, skiers, bilers can load a slope without causing a slide until . . . it slides, as if the cumulative load were the issue, which to my non-engineering brain does not make sense given the fragility of the snowpack as you've described. 

Condolences to all involved.


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## MPEARSON (May 23, 2005)

Hey Frenchy
I was wondering if the tree in the picture had maybe helped the slab break off. It's right at the break - maybe riding closer to the tree which will create some weak layers around from the heat from the tree. Were they high marking in different areas and as they got closer to the weaker area it set off the slab. Don't know !!!


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## MPEARSON (May 23, 2005)

Thanks for the pictures Frenchy


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## frenchy (Oct 10, 2003)

MPEARSON said:


> Hey Frenchy
> I was wondering if the tree in the picture had maybe helped the slab break off. It's right at the break - maybe riding closer to the tree which will create some weak layers around from the heat from the tree. Were they high marking in different areas and as they got closer to the weaker area it set off the slab. Don't know !!!



Not sure, wasn't around for the rescue on Sunday to ask questions. Our group debated on the location of the trigger when the slope broke but didn't come up with anything conclusive. I'm not sure the rider was anywhere near the tree, but have to imagine that you're right in that the tree created a weakness on the slope that acted as a path of least resistance for the slab to break. You'll notice the crown and flanks follow a straight line path from tree island to tree island. Overall though, I think the weakest part of the slope, and where the slide may have gotten triggered, was further downslope where the snowpack is thiner and weaker. This is total speculation.


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