Washington Terrain Ratings

Because of some recent discussions in the Trip Reports section, and in conjunction with some of my ongoing work with terrain/perception, I think it might be interesting to create terrain ratings for popular backcountry ski trips relevant to this community.

Continue reading if interested ( and feel free to disregard otherwise ):

ATES, a terrain rating system developed by ParksCanada et. al. for those who aren't familiar, has three levels:

Simple
Challenging
Complex

ATES technical model: www.btb.gc.ca/btb.php?lang=eng&cont=739
Samples: www.pep.bc.ca/hazard_preparedness/PCAN_Terrain.pdf

The Avaluator implements a grid that overlays the current forecast with terrain ratings, with the goal of helping a recreationist choose terrain appropriate for the conditions.

Here is a sample rating for backcountry terrain near Crystal Mountain. ( With explanations. ) This is classic "middle ground" terrain. In the wrong conditions this terrain is very dangerous but it's not obviously dangerous like the Mowich side of Rainier. I know some of the terrain in this area is used for fallback tours when instability is high elsewhere and/or because access is easy.

avalanchesafety.blogspot.com/2010/02/was...terrain-ratings.html

It would be nice to have ratings for the most popular backcountry trips for Turns-All-Year. How about if the community assigns ratings? I'm not familiar with many of the trail names or ski runs in this area, but just about anyone can use the ATES model and people who have undertaken any of these trips can read the technical model and vote on the rating. Maybe this would be enjoyable and useful for most everyone. ( But maybe not enjoyable for everyone. )

Here's the starter list ( from a map made by erikhenne: www.turns-all-year.com/skiing_snowboardi...dex.php?topic=9752.0 ) Rate trips you've skiied a few times or maybe if you've hiked there in the summer. Some trips will have obvious ratings, other trips will be more tricky to rate. Some trips might have sections of each. In that case, provide a list such as "Simple to Challenging" or "Challenging to Complex".

I think this is a very good idea. But I would note and other observers should note that it gets tricky for places that are not essentially a ski tour but rather an area of ski runs since the Avaluator system is designed to designate terrain according to the "basic" (My quotation for emphasis) tour route for a destination. In other words, each ski run would really have a different rating. So that for a place like Heather Ridge, there might be as many as 6 or 8 different ratings for different sets of terrain. The basic Heather Ridge tour following the ridge to Skyline Lake is probably Simple terrain, but at the steepest part of the ridge, I did turn around one time many years ago with stiff fresh windslab.

I actually tried to do this (absent the Avaluator) but with very similar destinations in Burgdorfer's first writing of his guidebook. Either Burdorfer or the Mountaineers may not have wanted the liability involved - is this right Rainier?

The idea makes perfectly good sense, and here is a fine place to accumulate the wealth. Guide books are published infrequently and routes are subject to a narrow frame of evaluation. I should think the implementation would be challenging, but then, I haven't jumped through your links to understand better, yet. It seems to me that a wikepedia sort of style, in that "definitions" morph with experience might factor well.

I believe it is the intention of the Canadians to go to a 5 step rather than a 3 step ratings system (personal communication).

I favor a five step system myself, with Step1 being "Avalanche Safe Terrain".  For example, the Yodelin trees West side, but forested (by "forested" I mean canopied tree cover - not gladed terrain where one can actually see a fair amount of sky) areas above 38-40 degrees would actually have a higher rating because they can slide with new snow instabilities on some occasions. Steps 2-4 would be the same as or similar to the current ATES definitions and Step 5 would be the kind of terrain that is always dangerous because of it's steepness and "ruggedness". For instance, Dragontail Triple Couloir would be Step 5, "Always Dangerous" because any fall with or w/o an avalanche can easily be fatal.

In this system, Heather Ridge would be Step 2, Simple Terrain for the easiest two routes to Skyline Lake - up the ridge or following the road. The road route is actually slightly more risky because of terrain traps along the route on it's easternmost switchback. But this would not be enough to cause the two routes to vary in rating. Yodelin in the open areas would be Step 2, Simple terrain as there are some easily avoided small avalanche terrain exposures. Thus, overall, Yodelin would probably rate as Step 2, Simple terrain under a five step system since the open areas are really part of the "Basic" tour to Yodelin. And, of course, there are two approaches to Yodelin - one through the ski area and the route from Smithbrook described by Burgdorfer. They are usually used to access somewhat different sets of terrain. I am less familiar with the ski area route as I haven't done that tour but a couple of times.

An example of Challenging Terrain might be Bullion Basin and Peak. Union Creek, though, would rate as Complex terrain, I would think, although there is a route or two in the Union Creek drainage that are less exposed.

Thanks for the input. Very interesting ideas from Gary et. al. I am probably too tired to write this post but I'm going to anyway.

Ratings should consider the entire route. While this can seem misleading at first, a "simple" partial route should have a different name and a separate rating.

As a whole, Union Creek is "challenging" and "complex" depending on your interpretation of several factors. Under computer analysis ( if you run some hard numbers ) a lot of the terrain in Union Creek has the same level of integral complexity and steepness as terrain that is maybe more "obviously dangerous" to the human eye.

This is best described as the difference between terrain that is visually striking and terrain with a generic appearance - except the statistical danger is the same ( and maybe the exposure is the same as well ).

So in terms of slope angles and slope shape, Union Creek ( which has a benign appearance relative to other terrain in the area ) travelers in Union Creek can be severely exposed but maybe not perceive the exposure. The accident record from the area certainly shows that some perception problems exist, and although easy access certainly plays a role, I can't help but think that access actually creates the perception problems in the first place. Anyway, enough out of my mouth about that for the moment.

Does Union Creek deserve a "complex rating". Well... that's for the white machine to decide. In the context of the entire rating system, no, I don't think it deserves a complex rating. I think it's challenging terrain. The trick is understanding that the rating system isn't just 1, 2, 3 in terms of exposure. The exposure increase between simple and challenging terrain is, I think, decidedly non-linear. Maybe in an exact world, Union Creek deserves a "complex" rating but you can go places that are a hell of a lot more exposed. The interesting thing about Union Creek is that its level of exposure is just past some statistical tipping point that lends a very dangerous character to an area.

Mt. Snoqualmie, while lacking the accident record, is another place that is past the statistical tipping point. Like Union Creek, easy access and a lack of awareness about the real degree of exposure in the area also play a role. Statistically speaking, the terrain has serious numeric pull. Relative to other terrain in the area, some of the runs seem like justifiable choices. That's why the ratings are important.

Besides my general obsession with terrain, this discussion of ratings was inspired by an interesting post about Phantom Trees in the March 2009 trip reports section. I don't pass judgement on others for their ski actions ... mostly because I have absolutely no shortage of lunatic idiocy in my ski record ... and otherwise.

Ok, I’ll bite on trying to evaluate some of the risk on Mt. Snoqualmie. I think this is an area in which Gary’s warning of applying this to an area of runs vs. a ski route applies, so I will try to be specific and describe just skiing climbers left in the trees up to treeline because that particular route sparked this thread and it’s one I do often for a quicky before work or before the kids wake up. I think other hazards exist if you skinned up the phantom, continued to the summit, slot etc so if this was meant to cover the whole route then those hazards could be added. My short answer is that it probably rates as challenging rather than complex but feel free to challenge any of this. I am curious what others consider it to be, I can take a punch, and I probably still have a lot to learn.
Avalanche Starting Zones – the phantom slide path, a handful of steep roll overs, the two cliff band sections, and the upper summit fields.
Avalanche Paths - The obvious crossing of the lower phantom risks would be during epic conditions such as when Hyak imploded earlier this season. Although on questionable days I do wonder while crossing the lower fields below the waterfall how much risk I am in since I haven’t had a chance to observe the snow on a steeper slope yet. I also wonder how close to treeline is safe near the opening before the summit? Could the summit slide and slam into the treeline? How far in would it go? At least by this time one has had opportunity to evaluate the snow on the way up, but that area is exposed to more elements that are yet unobserved.
Avalanche Runout Zones - Steep rollovers with benches and trees, there are a few gullies with runout zones going into the phantom and through the cliffs, and the two small cliff band sections themselves pose a hazard.
Steep Terrain - Much of the terrain is steepish and could be avalanche prone. That’s the appeal really, not much time is wasted to get a decent amount of vertical and ski right back to the car.
Open Terrain - Some glades open up, the phantom is open.
Line-Of-Sight - The trees have limited line-of-sight.
Terrain Traps - There are some terrain traps such as convexities, trees, depressions, gullies, man eating creek hole monsters, and the alpental bomb squad.
Exposure Time - I feel exposed crossing the lower phantom but if it was a day when the danger was that extreme I wouldn’t choose this route. If I happen to be first cutting the track up the two small cliff sections it crosses my mind that it would be a bummer to have the slope come down on me. I also think there is some exposure near the treeline as the open slopes to the summit could possibly break loose and deposit into the trees.