[Tagging] Feature Proposal - Voting - Couloir 2

Fri Feb 19 17:40:13 UTC 2021

OK, despite the rather technical explanation I was able to understand
it. But it doesn't make the description in the proposal wrong.
If I refer back to the old original disapproved proposal from 2012
(https://wiki.openstreetmap.org/wiki/Proposed_features/couloir) it is
exactly what it said there, except of the missing steepness details.
Neither does the new description from Yves said this, you just introduce
a new steepness criteria.

I propose you guys as specialists find common ground on which criteria
are applicable here to distinguish one from the other.

As a non-specialist my analysis so far:

                width                                 ridges & summits 
        caused by                       terrain

valley        wide >100m                         multiple               
        rivers or ice erosion        in mountainous terrain only ?

gorge        narrow <100m ???                single ????        
          river or water flow                not part of cliff

also outside mountaineers terrain

gully          small scale                            single ???? 
               river or water flow                 also outside
mountains                                  what is a few ten meters
?                                                                                 
is a BARRIER, needs climbing

couloir         1m < 500m ????                 single ????           
    might be river or water flow    only in solid mountain mass

but includes other causes     is not a BARRIER, doesn't need

climbing, can be hiked, skied.

and distinguished from other specific mountain features by it has steep
sides on both sides, other named featurs the steepnes or character is
one-sided.

So looking at the above it seems clear to me (not saying correct): a
couloir is distinguished from a gully by mainly 2 criteria: it CAN have
a larger width but the main criteria is the terrain: IS NOT A BARRIER
that needs to be climbed, only in SOLID  MOUNTAIN MASS.  A gully by
definition needs to be climbed ?

Hope this helps, please agree or find a compromise.

Greetings,

Bert Araali

On 19/02/2021 18:39, Kevin Kenny wrote:
> On Thu, Feb 18, 2021 at 7:22 PM Bert -Araali- Van Opstal
> <bert.araali.afritastic at gmail.com
> <mailto:bert.araali.afritastic at gmail.com>> wrote:
>
>     Gully or gorge = created by flowing water or ice, also applicable
>     for desert
>
>     Couloir = similar appearance but not created by erosion but by
>     other phenomena which only appear in mountains.
>
> That's a part of the description that I found confusing, because in my
> part of the world, virtually all surface topography is erosional.  
>
> Even the large couloir for which I posted a video link earlier (I
> since discovered a trip log with excellent images
> at https://alavigne.net/Outdoors/ImageGallery/2015/06-27-TrapDike/?n=2#id=54959)
> has a complex history. The rock on either side is anorthosite gneiss,
> and is among the oldest rock on the planet, being on the fringes of
> the Canadian Shield.  The gneiss is broken by a newer intrusion of a
> narrow dike of gabbro (essentially, a coarser-grained form of
> basalt).  Over the eons, repeated glaciations, avalanches, and
> freeze-thaw cycles have eroded the gabbro away leaving the deep,
> narrow, steep chute that we have today.  Because the climate here is
> relatively wet, a stream does flow in the couloir (and the hardest
> part of the route is ascending the two waterfalls). 
>
> Farther south, the Catskill Mountains aren't mountains at all,
> geologically, but rather aretes of sedimentary rock in a dissected
> plateau.  They still have features of similar
> topography.  https://i0.wp.com/mountain-hiking.com/wp-content/uploads/2019/10/Twin-Cave.jpg
> and https://i.redd.it/ho2zisofspn41.jpg are sculpted purely by
> erosion. (They don't look like alpine couloirs, because they're below
> the tree line, but they get the same sort of conditions in winter and
> offer similar lines of ascent.)
>
> I would agree that you see couloirs only in mountains (or other cliffy
> features such as canyon walls), because only mountains are steep
> enough to have them.
>
> To me, the distinguishing features are that a couloir has rock walls
> on both sides and a steep gradient. Usually the climbing is at least
> class 3 on the Yosemite scale, and may be considerably more technical,
> particularly when there's ice about.
> -- 
> 73 de ke9tv/2, Kevin
>
> _______________________________________________
> Tagging mailing list
> Tagging at openstreetmap.org
> https://lists.openstreetmap.org/listinfo/tagging
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/tagging/attachments/20210219/8cdee223/attachment-0001.htm>