Home > Trip Reports > Chinook Pass June 20

Chinook Pass June 20

6/15/10
WA Cascades West Slopes South (Mt Rainier)
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Posted by RonL on 6/20/10 10:13pm
The coverage is still great and nothing is refreezing at these temps so the snow was just as good first thing in the morning. Visibility was poor but it was just a light mist while I was there rather than the heavy rain I drove back in. It was a great way to kick off Fathers Day.
Ditto on all that.

Not trying to start any sh*! here, just looking for some answers about spring avalanche rules of thumb since most (if not all) of the AIARE curriculum is focused on dry slab avalanches.

if its not freezing isn't it a good idea to stay off of it?

Really - not trying to call you out, this is something I want to learn about.

Thanks

I was up there as well.  And the snow was very fun to ski.  Despite not freezing overnight the snow was still packed and solid because the temperatures stayed pretty cold throughout the day.

A picture from the top of Yakima peak

I am in no way an avi expert but I didn't observe any instability. I didn't exactly dig pits or anything but it all looked pretty consolidated and as eolson pointed out there wasn't a dramatic temp fluctuation going on, especially as early as I skied it.

author=hwy2 link=topic=16973.msg71555#msg71555 date=1277241086]
... just looking for some answers about spring avalanche rules of thumb since most (if not all) of the AIARE curriculum is focused on dry slab avalanches.
if its not freezing isn't it a good idea to stay off of it? ...


Sounds like a fair question to me.

Bear in mind, I’m the second "Ron" on this thread that is no snow scientist. I’m just a backcountry skier that loves the mountains and has managed to find safe (but not necessarily steep) places to ski in the mountains in just about any avalanche conditions (so far – knock wood – that’s my head you hear making that hollow sound :)).

So here’s my overall reasoning with regard to avy danger for skiing just about anywhere I ski and Chinook this last Sunday in particular.

The NWAC, in my opinion does about as good a job as any in the country with the equipment and resources they have. The major disadvantage they have in their work, however, in my opinion, is that they have to come up with a statement that fits a very broad geographical area covering multiple aspects, angles and elevations. While they do an exceptional job at generalizations regarding aspects and elevations, there isn’t much they can do about being more specific about a particular intended destination. In the case of last weekend their Spring Avalanche Statement is information that I believe every backcountry skier should have in their head and be aware of. Is it data that should keep you at home? Well, not even close in my case, but I always appreciate their insights. The NWAC avy statements are just a part of the broad array of data with which I come to a “gut instinct” as to how steep a line I am willing to ski, and ultimately, where I ski.

So just what is this “broad array” of data that I speak of?
Well I have a pretty simple mechanical mind. So with me it starts in the fall. I like to know what’s under the snow and understand its composition. I try to get out every weekend year ‘round. In Sept, Oct, Nov, I may only ski one weekend a month depending on the coverage that year. But I’ll still do “recon hikes”. So before the new snow starts to fall I have a pretty good idea of where the snowfields are that have managed to hold snow through the summer. Those patches usually make good skiing bases for trips to ski on the “new snow” during the first few light dumps of the season rather than ski on the bottomless “rock gardens” that destroy skis and break legs. Regardless, this is when my “snowpack data gathering” starts for the season.

As the season continues, I follow the snowpack by watching the weather and telemetry as the snowpack gets laid down. I especially watch for early winter cold spells that develop hard crusts which might eventually develop into persistent buried weak layers that could lie in wait for just the right conditions to release a big surprise. After following the weather and telemetry each week, before leaving home on the weekend I check the latest avy forecast paying special attention to the “snowpack analysis”. I know that they make trips out regularly and dig pits too, so I like to see if my assessment matches up or differs with the pros. Once on the snow my info gathering starts to get more refined; more specific to that particular locale. I may not dig a pit each time out but I’m always probing looking noticing, doing hand tests, ski cuts, etc, trying to decide which aspect will ski the best and be least likely to slide.

My personal “watch it” conditions are recent and heavy precip, especially when temps are increasing. I am usually of the opinion that nothing good can come from skiing lines over 25 degrees under those conditions. On the other hand, I feel that, generally, the maritime snowpack is the most user friendly of them all, and (somewhat over simplified) if one gives the storms a day or two leeway and is careful around harsh temperature upswings this is generally a pretty safe part of the country in which to ski. These thoughts may be as close as I get to any “rules of thumb”. Not sure whether that’s good or bad.

I also pay attention to my ski partners (especially the females – less chance of testosterone caused impairment of judgment ;)) and I try not to be the “last word” on  whether or not we ski a line or not. I feel that ski stability tests have their place but to me the best test of all is tying myself to a tree or improvised anchor and then jumping up and down hard on the most likely roll of a slope to gain confidence in its stability.

So good or bad that’s my general overall “modus operandi”.

So what about last Sunday at Chinook?
To start with, I skied 3 out of the last 4 Sundays on Naches Peak.
The nice thing about the Chinook road cuts is that since they don’t clear the road until the spring, the road cut (at least on the uphill side of the road) is usually a fairly good representation of the existing snowpack. Shoveling or kicking steps in it give you a pretty good idea of the layers and the consolidation. A month ago the consolidation was horrid. A foot of boot penetration by the time I climbed to the top of the 10 ft road cut at 8:00 am. About a foot of ski penetration by about noon on northerly aspects. Southerly aspects about 6 inches. Lots of “hissers” or wet sloughs after about noon on southerly, sun affected, aspects. Didn’t ski anything steep that day. The big avy that was reported was on the east aspect on a very steep pitch. No surprise there, eh? The NWAC guys pretty well called that one.

Since then there been a few warm days (causing settlement) and clear nights (allowing the snowpack to refreeze even if surface temps fail to get down to freezing). The last time I skied there (two weeks ago) it had firmed up quite a bit. Since it was overcast Saturday night I didn’t expect hard frozen snow but I was still hoping for firm, fast snow on Sunday morning. Boot pen on top of the road cut at 8:30 am was about an inch. Ski pole pen averaged 2 to 4 inches, ski pen ½ to 2 inches on 20 to 30 degree slopes – a little more on steeper aspects. I skied pretty much the northwest aspects and felt I probably could not have started an avalanche even with a D-9 Caterpillar with ripper teeth on the back. Was done by 11:00 and the snow had hardly softened at all, still no drips from the trees, as it was still overcast and no more than 5 degrees warmer.

There you have it – my short version answer to your question :)

Now there’s a lot more knowledgeable folks than me regarding snow science that post on this board. Maybe they’d like to refine the discussion a bit more pro or con.



Well documented dissertation Ron, lots of good info there that reads pretty similar to my way of thinking. So either we are both way off or on the right track.
I would offer that the cornices at this time of year can be of concern, especially the hanging ones. Some of the ridgeline ones have settled back, but still keep a wary eye.
Good read is the book Snow Sense By Jill Fredstor and Doug Fesler to get started-I read it all the time, there is always something I pick up like Ron J's thesis.

Thanks for the kind words, Joe.
It's nice to know that at least one of the most experienced of the survivors on the forum confirms some of my simplistic logic. :)
The comments about cornices and Snow Sense are both great additions.
Thanks.

I'm heading to chinook right now and will be keeping a sharp eye out for cornices.

Thanks for taking the time to share your thinking.

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RonL
2010-06-21 05:13:27