How specifically do you define a pass?

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SWriverstone
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How specifically do you define a pass?

Post by SWriverstone » August 16th, 2021, 1:13 pm

Technical Trivia Topic Here!

I work for the Pacific Crest Trail Association, and for a long time we've wrestled with a particular metric we've always been dubious of:

How many "major mountain passes" does the PCT cross?

At some point in the past, someone came up with the numbers 50, 57, and 60. We have no idea today where those numbers came from, and have no reason to believe any of them are accurate.

Obviously, it depends on how you define a pass. There are very specific criteria for defining prominence...but I've never seen anything so specific for defining a pass (or a "major pass"). Yet PCT hikers (and hikers generally and explorers historically) routinely talk about passes like they are peaks (because the big ones involve a climb).

One way would be to set a "minimum ascent required" to summit a given pass, then count all that meet that minimum. But where do you set the start of a climb to a pass? For some it might be obvious...but for others, you might have been climbing for miles when you begin the final ascent.

Another way might be to just count the named passes (on the assumption that said pass sufficiently impressed enough people to give it a name). Obviously there may be hundreds of unnamed passes that might still technically be passes by any definition (other than lack of a name).

So I figured I'd float this here to see what arcane info folks might have. :-)

Scott

Aimless
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Re: How specifically do you define a pass?

Post by Aimless » August 16th, 2021, 1:50 pm

Defining a pass is relatively simple. It is the lowest accessible point in crossing between two valleys. The problems are introduced with the modifiers "major" and to a lesser extent "mountain". These introduce elements that are quite subjective and can only be 'accurately' defined by introducing wholly arbitrary criteria.

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SWriverstone
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Re: How specifically do you define a pass?

Post by SWriverstone » August 16th, 2021, 2:56 pm

Thanks Aimless. I don't disagree. Though I'm curious now to go back and look at the criteria for prominence. Because I'm wondering if there aren't at least a few that are purely arbitrary there as well.

Wikipedia's definition of prominence says it "measures the height of a mountain or hill's summit relative to the lowest contour line encircling it but containing no higher summit within it."

Seems like something similar could be defined for a pass? (Because isn't a pass just a type of high point?)

Scott

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retired jerry
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Re: How specifically do you define a pass?

Post by retired jerry » August 16th, 2021, 3:28 pm

A pass is like a saddle

If you go, for example, forward or backward you go downhill. If you go right or left you go uphill.

Yeah, you could do something like prominence. You have to go at least some specific distance down and up for it to count.

Sometimes, I'll go up to the top of a ridge, then down the other side. Sort of like a pass. At the top, forward or backward is downhill, but right goes uphill, left goes downhill. I sometimes call that a pass although maybe that's not proper.

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Re: How specifically do you define a pass?

Post by Aimless » August 16th, 2021, 4:32 pm

And once we have succeeded in this arduous process of satisfactorily defining exactly what constitutes a major mountain pass it will allow us to apply it to the PCT and arrive at... a number! :D

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teachpdx
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Re: How specifically do you define a pass?

Post by teachpdx » August 16th, 2021, 5:57 pm

It’s an odd metric for a ‘crest’ trail, which would in theory follow the crest and therefore meet every pass on that crest in a perpendicular fashion.

Think of Lolo Pass, which makes my point. It’s a ‘pass’ along the PCT, and certainly a traditional pass when driving Road 18, but when hiking the PCT you descend to it, then climb from it, meeting the pass at 90 degrees. So you do a named pass without any climbing. Same with Wapinita Pass, Barlow Pass, McKenzie Pass, Santiam Pass, the pass at Potato Hill north of Adams, White Pass, Snoqualmie Pass, etc. All of these are ‘major mountain passes’ but because it’s a crest trail, these passes are low points instead of high points.

There are also cases where the PCT may climb around the nose of a ridge and then descend to the next valley, like Jerry said. It may involve a very significant effort on climb and descent but it’s not a pass by definition.

Maybe it’s better to count summits or high points/crests. And that you can define more easily using the ideas of prominence, and not being stuck with an ill-fitting definition of ‘pass’. Like on the west side of Hood, going from Zigzag Canyon, over Paradise Park and down to the Sandy is a significant climb and loss, but not a pass.

If I were defining this by high points, it would be: 1) rising from and then descending back to a similar elevation, or geographical landmark (valley to valley, canyon to canyon, saddle to saddle), 2) probably 500’ of gain/loss minimum, and 3) minimum sustained grades of around 8-10% or more.
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retired jerry
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Re: How specifically do you define a pass?

Post by retired jerry » August 16th, 2021, 7:03 pm

Good point about following a crest teachpdx

The passes are low points, not high points

I hadn't thought of that

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Chip Down
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Re: How specifically do you define a pass?

Post by Chip Down » August 16th, 2021, 7:36 pm

I don't see how you can possibly come up with a satisfactory solution to this conundrum. I think your only hope of avoiding severe psychological trauma is this:
SWriverstone wrote:
August 16th, 2021, 1:13 pm
Another way might be to just count the named passes (on the assumption that said pass sufficiently impressed enough people to give it a name). Obviously there may be hundreds of unnamed passes that might still technically be passes by any definition (other than lack of a name).

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mjirving
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Re: How specifically do you define a pass?

Post by mjirving » August 16th, 2021, 9:01 pm

Per the comments about it being a crest trail, it seems that the trail passes (high points) are the spirit of it rather than the low passes that run perpendicular (like Lolo Pass etc mentioned above). Like forester pass and glen and Muir, red pass in Washington etc. Those would be the named ones at a minimum “major” and then some prominence factor with the spirit of it being entering and leaving each valley on the trail. (One of my fav activities of hiking the PCT)

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texasbb
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Re: How specifically do you define a pass?

Post by texasbb » August 17th, 2021, 4:27 pm

The direction you happen to be moving when you arrive at a pass has no bearing on whether or not it is a pass.

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