Snowboarding Forum - Snowboard Enthusiast Forums banner

CAIC reporting avy death on Wolf Creek Pass

4K views 29 replies 7 participants last post by  ETM 
#1 ·
No other details available right now. RIP

That would be #6 in CO, our yearly average - in mid-February. :(
 
#7 ·
can someone tell me why CO snowpack is generally weaker than say a PNW snowpack? reason i ask is i have been doing a bit of research on avalanches and it seems that CO and UT seem to always lead the nation in avalanches and any deaths. Just curious as to why they are more common than other snowfields.

Its also very hard to find any information on avalanches in Australia as we rarely have the snowfall amounts that would cause a slide.
 
#14 ·
can someone tell me why CO snowpack is generally weaker than say a PNW snowpack?
Think of facets are more angular grains, not rounded. Rounding grains actually strengthens the snow pack. They pack tightly and form strong cohesive bonds. Facets grow and become very angular. At the bottom of the snow pack they are absolutely huge. Sugar snow. Very little to no cohesion.

Remember the big October storms we got that got everyone doing the happy dance? Well it's that storm that is now keeping the ski areas from opening their best terrain and has become the major problem in the backcountry. We got that snow and like clock work it sat there for weeks without new snow. Facets grew and it become very weak. Then the snow started in earnest and that shallow layer became a non supportable layer that is over a foot thick. Just to add to the problem, at some point, we got a storm or two in late November/early December, I forget. It laid down 5-10 inches. Then it didn't snow again for a while. It evidently came in warm, because at the interface with the ground facets to the newer snow there is a melt/freeze layer. Very thin, less than an inch in most spots. Very brittle. Add to just on top of it, is a near surface faceted layer. It's less than a quarter inch, but that layer is a killer. So you've got a thin hard but brittle slab sandwiched between two weak layers.



RIP.
just to hopefully simplify a little: when new snow sits for a while in cold, clear weather the structure of the snow changes from pretty flakes that we all know and love to rounded or faceted.

this is a real problem in CO because it actually stays cold enough once the winter starts to produce this layer, and as long as it isn't snowing it should usually still be cold enough to cause it.

in the PNW we can also get a snowfall followed be a week or weeks of cold, clear weather. a big difference is that we typically get storms that start off with an extreme low front (warm and wet coming off of the ocean) so even if the storm ends up at 18 or 20 degrees, it probably started closer to 28 or so. it will also frequently get 32 degrees or higher in the mountains at periods throughout the winter and these melt-freeze cycles will consolidate the snowpack.
 
#8 ·
To accurately compare the figures from place to place you need to have data on exactly how many people venture into the back country in each zone. 6 deaths in one place might sound a lot but if there is 20x more people out there then the death rate per head is actually less.
In Australia we really dont have many people out in the back country.
 
#10 ·
The CO snowpack is a continental snowpack and a bad one at that. It sucks because it's relatively shallow, cold, and dry. A shallow snowpack = a weak snowpack. To make it worse, we tend to get frequent small snows and that leads to a lot of layering. The interaction between these layers varies and creates additional weaknesses.

This year is especially bad because it's a bad snow year. We got very little snow for much of the season and all that snow turned to facets. Facets are basically snowflakes that have rounded off. Think about a nice, fresh snowflake. It has all kinds nice structure and angles to it that bonds well with other snowflakes. Facets don't bond. They create a very weak layer. Now we're starting to get some snow. So on top of this weak layer of facets, we're adding weight and we're adding weight in layers of snow that are relatively well bonded together compared to the base. This creates a slab. When you have a slab sitting on top of a weak layer, you've got the perfect recipe for avalanches. That's what we have now. Shit is fucked.

Yes, the amount of people in the CO BC contributes greatly to the number of deaths, but the CO snowpack really is THAT dangerous.
 
#13 ·
Think of facets are more angular grains, not rounded. Rounding grains actually strengthens the snow pack. They pack tightly and form strong cohesive bonds. Facets grow and become very angular. At the bottom of the snow pack they are absolutely huge. Sugar snow. Very little to no cohesion.

Remember the big October storms we got that got everyone doing the happy dance? Well it's that storm that is now keeping the ski areas from opening their best terrain and has become the major problem in the backcountry. We got that snow and like clock work it sat there for weeks without new snow. Facets grew and it become very weak. Then the snow started in earnest and that shallow layer became a non supportable layer that is over a foot thick. Just to add to the problem, at some point, we got a storm or two in late November/early December, I forget. It laid down 5-10 inches. Then it didn't snow again for a while. It evidently came in warm, because at the interface with the ground facets to the newer snow there is a melt/freeze layer. Very thin, less than an inch in most spots. Very brittle. Add to just on top of it, is a near surface faceted layer. It's less than a quarter inch, but that layer is a killer. So you've got a thin hard but brittle slab sandwiched between two weak layers.

I observed a lot of this on Vail Pass yesterday. At the slope we usually start with there was a fracture line from a slide there earlier this week. It slid on top of that brittle ice layer, but did not step down and take out the ground facets. Awesome. I did an ECT on what was left, got a full propagation at the second strike from my elbow. I'm calling it a Quality 2 shear, but some might call it a Q1. If there is a Q 1.5 that is what I'd call it. Either way it was a huge red flag, and we stayed well away from that aspect and the cliff line. We chose more broken terrain with wide open run outs to slide out on should it slide. Having stuff to bang into like trees is not a good thing. Something to be super mindful of this season. What is below you. I believe a lot of those zones, the slides are not big enough to bury you completely. The problem is the terrain you are getting carried into, is enough to beat you to death, or the terrain has a feature that facilitates you getting buried deeply. We've seen this a few times already this season. Many of the deaths have been from trauma. The sidecountry skier outside of Snowmass triggered a very small slide. A slide that you'd normally just walk away from, without needing to be rescued. The problem was that the bottom of the path ended in a v shaped gully that facilitated him getting fully buried. A terrain trap. You can look at the report and pictures here. You can see that the slide was barely 30 feet tall and not much wider than that. The terrain choice is what killed him here.

The Wolf Creek area is a bit different. Generally speaking the snow pack down there is in pretty good shape. They do have several layers of surface hoar that is now buried. Creating some problems. In well treed zones and a lot of zones, it's perfectly fine to be playing around. 40 degree widely spaced trees in Gibbs creek is not that area. I have no idea why one would think that was a good zone to play in. I know from riding with locals on the pass that Gibbs creek was a zone that they wouldn't even consider riding until stability was decent on the pass. At least moderate all the way around, and usually some low avalanche danger at certain zones and aspects. Not an area you want to mess with when considerable is the overall danger rating. I think the desire to ski "rad" terrain, and the lack of it even in bounds is helping people make some irrational choices. Plus the factor that backcountry riding is now the kewl thing to do is getting people out there who do not understand or chose to ignore the warning signs. The report is also that he was a ski patroller at Keystone. Even the most experienced can make critical mistakes. It's a bummer, because there is plenty to do at Wolf Creek pass that is safe, but offers very steep, although short shots, that are very low consequence if they should slide. Why he chose such a high consequence area, I do not know.

RIP.
 
#16 ·
right, so i didn't talk at all about temperature gradients in snowpack because i didn't want to spout too much or go over anyone's head - but the difference in the temperature throughout the snowpack is a critical element.

anyone intending to get into the BC needs to read Bruce Tremper's book - at least twice. there is way more information then we can effectively talk about on an internet board, and you can be sure that it is explained better than i can - since i am just paraphrasing him anyways :laugh:
 
#17 ·
Keep it simple. I am all for it. I know I went on at length in my post. I am assuming some level of knowledge from the people participating in this discussion. For those who this goes way over your head. Reading Bruce Tremper's book, Staying Alive in Avalanche terrain is a great read and for around $20. Much cheaper than taking a level I avy course. It's a good read for those of you who are just getting interested in backcountry riding, but are not ready to take the plunge yet.
 
#18 ·
i'd say if you read that book 2-3 times, understand what you are reading, and then go out onto snow and dig pits and recognize what you see and can make some evaluation - then you pretty much HAVE taken a level 1 class....







still take a class, and remember that you are now far more dangerous than when you knew nothing and were to scared to go out there. you now think you know what you are doing, but you will do far stupider shit with your false sense of confidence.
 
#19 ·
Yeah, if you are getting into it, you MUST take a level I at some point. The nice thing is, if you've read Tremper's book (which covers more than a Level I course), you'll be way ahead of the class when taking the course. I had read it before taking my Level I and I was way ahead of everyone else in the class. So much so, I was able to pull my instructors aside and look at more advanced stuff, because I had already picked up on the basics they were teaching.
 
#23 ·
For sure. The snow pack is inching up to a tipping point. To be honest I wish we would get a good dump that would just overload the faceted layer at the bottom altogether. I don't think it's going to happen. If we do get an avy cycle, it'll probably just be on that layer just above the ground facets, leaving us with the same damn problem. I also don't think this storm is going to be enough for that. It will be enough that a given slope could be overloaded with the addition of say a snowboarder...
 
#25 ·
It's all I've seen. I don't blame them, this is a junk show weekend and the potential for multiple accidents are there. Especially around the Front Range, which could stretch S&R very thin. Seems like every news source is posting the warning. Also, add to the fact that we are at our seasonal average with a solid two months plus to go. It could be a record year. Which is also the last thing we need. Then some jack ass politician will start talking about responsibility, what can we do about it, etc...
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top