RFC: hiking_exposure key (along with hiking_technique this disambiguates sac_scale)

In french (or maybe Swiss French), we also say “aérien”, the exact “airy” translation in the same context.

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And I can’t resist sharing an example. Difficult alpine hike, or easy climb. Definitely some gas.
https://www.youtube.com/watch?v=u5zv_2tQhXg (watch around 1’10")

As an example, here: “Un passage aérien permet ensuite de surmonter une paroi étagée.”

I live next to the Dent de Morcles and can definitely confirm that it is quite “airy”.

I was really impressed until I saw the rope haha (still a little impressed honestly). That’s definitely some fatal_exposure there and much more than I’d be comfortable doing unroped.

Some interesting examples elsewhere, it starts off with casual_walking, in the next few seconds has surefooted_walking with both no_fall_danger. The chute around 0:30 looks more like scrambling than use_of_hands and I’d probably put it at exposed vs short_falls_possible as it steepens up enough that it seems like someone just tumble down it.

This was a fun feature in Yosemite and about where my casual “hiking” / scrambling limit is. The majority is not as directly exposed as it looks if you wiggle around it and come from the back aside from the summit block and a few moves before it. I’d put the summit as fatally_exposed even though it’s not quite so knife edge as the previous video.

While this is not really the right place for feedback on the link below (temporary WIP website), the 3/4 PG here would map to short_falls_possible scrambling, 1/2 R would be exposed surefooted_walking to use_of_hands, and anything with X would be what I’d consider fatal_exposure at least on semi-technical level for off-trail hikers and backpackers. It’s geared towards a US audience so is based off of YDS. I basically copy pasted it over here, but it’s grown nicely since to fit a more casual & trail centric general audience. :slight_smile:

I have another set old photos I pulled out to parse for this but haven’t gotten around to.


I honestly don’t have a great intuitive feel for stuff below what I’d consider fatally_exposed as that’s the only thing that really gets me feeling like I need to be really sharp. It’s something I’ve been trying to be more aware of as I tend to downgrade exposure on terrain I’m comfortable on - I have to try and extrapolate out to what I would have thought when I was younger / people I know etc.

So… what if we just drop the term exposure and only mention it in value descriptions? 5 would be exposed, 6 fatally/severely exposed in mountaineering terms etc. It’s currently the following:

Rename the key to something like hiking_fall_risk (technically only the last two values really deal with real exposure) and values are:

long could be replaced with fatal.
short could be replaced with minor or moderate perhaps.

This would make more sense to the average person I think.

Actually 2 isn’t quite “no fall risk” as someone can trip and fall over a root or something on a surefooted_walking path. I think this is probably a more accurate way to describe things:

likely could be problematic, as a tourist is more likely to fall on fatally exposed terrain than a mountaineer, but I think that captures “direct exposure” vs “indirect exposure” in a more casual friendly way. probable perhaps?

There should be some way of showing that 5 is scary, you could possibly die, but you aren’t likely to - a 9" wide even trail with a fatal drop on one side etc. 6 should be something like “oh someone died falling there, that makes sense to me”.

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Would it be good to separate likelihood and consequence? It’s getting long. Eg maybe a small chance of fatality could still more dangerous than a large chance of slipping to light falls. The list makes it seems =moderate_falls_likely is a possible candidate, while it’s not yet.


I’m not a mountaineer in any way, although we do go bush-walking (hiking).

When I started reading, it took me several paragraphs & looking at the Wiki link to realise you were talking about the risk of falling!

When I saw “exposure” I immediately thought you were talking about being exposed to extremes of temperatures (both cold or hot) & other types of inclement weather!


Two alternative options:

hiking_vertigo={low, high, extreme}

hiking_perceived_height=XXX (in meters)

I guess this is mapped here Way: ‪Traversée du Gerbier‬ (‪830726688‬) | OpenStreetMap ? This definitely is out of range of the sac_scale hiking scheme. It is not tagged such, rightfully.

If you asked me, highway=path is trolling there.

I see, you did away with “caution”, a term that I could immediately familiarize with. It did remind me though of a place where I said to myself, now you gonna watch your step, even though I did not feel exposed, it felt airy neither (luftig in German.)

The next day, a hiker fell to death in the very location, when she lost balance swapping sticks from one hand to the other. The path on OSM is a T3 and that seems about fine, as there are assistive ropes all over. It is a crowded place, lots of hikers out for the scenery. I talked with some of them. Coming straight from urban flatland, they can walk hours a day for over a week, but they hate mountain paths.

As we were doing earlier today, on a track around the lower edge of a rock formation, & I thought about this idea!

We were on a formed, but moderately rough, track, & felt totally “safe”, but if you’d slipped / tripped / anything off the edge of the track, it’s ~50m down on a steep angle, full of boulders & trees!

Certainly injured, likely seriously, possibly fatal.

How does that equate to your suggested categories?

when I looked it up to find the video, I found a couple of texts that presented it as halfway between “vertigo hiking” (I did not know that expression) and “easy climbing”. As far as I remember, this is the only place of the route where you need to use hands.

It seems to me that we are struggling with two intertwined concepts: danger, and perception of danger. The point being that perception sometimes increases danger for good.

In theory, but that is probably too granular for a general hiking tag. I’m thinking that people can tag localized systems on top of this if they want - BMC, UIAA, etc. Having the technique on there as well helps with this - casual_walking vs scrambling have different likelihoods without getting into very fine details of terrain composition etc.

This has added two tags since it was made (unknown which isn’t really a meaningful value) then the airy_but_safe one which seems like a good idea.

what would make more sense? hiking_fall_risk or hiking_fall_danger come to mind for me.

I was thinking this over in my head and I think “long” falls is a lot simpler. I get hung up sometimes with exposure - “well I probably wouldn’t die if I fell here… maybe just some broken bones etc”. Someone can also die falling if they trip on the sidewalk and crack their head or snap their neck, so “fatal” isn’t reasonable. If I think in terms of mountaineering exposure I feel like if you aren’t climbing up a steep wall or on a knife edge ridge like the video above it’s wussy to think it’s the highest exposure rating.

Going back to long_falls_possible makes sense I think. It’s not like you’re going to be on some talus where you might have a small fall, or a trail where you have a trivial one, etc.

Without having been there I can’t really say (how steep, how wide, did traction seem good, etc) it’s hard for me to adequately label something. The Spencer Trail trip report I linked above falls into a similar category I think, many people do it, but some people don’t and even though a fall isn’t "likely’ it is possible there in a way that it just isn’t on flatter terrain.

I’d go with hiking_technique=surefooted_walking & hiking_exposure=long_falls_possible in that case,

This seems less parsable than a hiking_fall_risk, I’m not sure I heard the phrase vertigo hiking before and vertigo is a pretty specific condition.

Yeah. What are you being cautious about? Losing your footing and twisting your ankle or the toes of your boots being 3cm from a sheer 1000m drop?

Yes, but generally perception is there because of some danger.

Comfort with technique will also help alleviate perceived danger - a hiking_technique=casual_walking and hiking_exposure=long_falls_possible seems much more manageable than hiking_technique=use_of_hands and hiking_exposure=long_falls_possible to a non-mountaineer. I think combining those tags tells a useful (if still somewhat vague) story that has more information than just T4.

I think having some notes on common perception is useful, but trying to have a tag which is only perception based wouldn’t be useful unless there was some mechanism for multiple users to “rate” a hike and have different results show up etc (which isn’t in the scope or functionality of OSM).

I think the following make the most sense to me (a mix and match from my different versions above). The airy_but_safe could even go above short falls if we balance by perception vs risk. I think that actually makes some sense progression wise.

casually rewritten key overviews


terrain: you are unable to fall much further than onto the path you’re walking on. you might want to watch your footing on hiking_technique=surefooted_walking to avoid twisting an ankle or bruising your nose etc, but that’s about it.

psyche: anyone with standard coordination and balance won’t have fall risk affecting their comfort or discomfort of the path.


terrain: are are using your hands for balance on talus, going up a moderately steep slope, mantling up to a higher ledge, very near a short cliff, or on a very short scramble. you may fall, but it generally won’t be more than ~2-3m above the ground. still enough to do damage though!

psyche: some people will be very uncomfortable, the vast majority will be aware of it but not be too worried depending somewhat on the hiking_technique=* level.


terrain: long falls are possible around you, but there is human construction preventing or protecting you from them.

psyche: if you’re afraid of heights you won’t like it, but you won’t fall barring negligent behavior.


terrain: the terrain allows for longer falls that are either near a ~vertical drop or down a steep slope you wouldn’t be able to easily stop yourself on that could result in serious injury or death, but there’s enough space between you and the fall that you could still likely recover from a mistake or loss of traction without falling (or have it be a short fall instead). serious injury or death is still possible on this terrain, but would not be expected.

psyche: many people will still be fine doing this at lower hiking_technique=* levels, but people that are sensitive to heights could be very uncomfortable. experienced people with a “head for heights” will notice the risk but probably not be overly concerned by it.


terrain: the terrain allows for longer falls that are either near ~vertical drop or down a very steep slope and it is “directly exposed” enough there is very little to no margin to recover from a loss in traction. a single mistake could easily lead to serious injury or death.

psyche: most people will be uncomfortable on this terrain regardless of hiking_technique=* and even experienced people that are comfortable on it must take it seriously even on lower hiking_technique=* levels.

Basically what a mountaineer would consider "exposed’ is probably only the final value, and we’ll hem and haw and be “awww shucks that’s not severely exposed, let me tell you about the time…” People can add climbing or mountaineer ratings for more information if they want at that point, but it seems like for the general public this tells a useful story. :slight_smile:

I still don’t like long_falls_likely - it’s useful as a step up from them just being “possible”. I personally would do indirect_long_falls and direct_long_falls but that’s probably too mountaineery!

From my partner:

Yeah the “long falls likely” value is the weirdest one there. I get that it’s indicating increase terrain difficulty which means increased risk & trying to keep the phrasing consistent among levels but ends up sounding like a statistical prediction

Could you just do high_long_falls_risk to bookend trivial_fall_risk? Although then there’s confusion between high as in “likely” vs high as in “height”

Could do:





I don’t really like any of those.

trivial_fall_risk could be changed to trivial_falls_possible. or actually just trivial.

If the key is hiking_fall_risk, how about the following values:

1. trivial
2. short_falls
3. airy_but_safe
4. long_falls
5. long_falls_close
5. exposed_long_falls

and many other, even worse attempts

another approach with hiking_fall_risk

1. trivial
2. short_falls
3. airy_but_safe
4. long_falls_low_risk
5. long_falls_high_risk
1. trivial
2. short_fall
3. airy_but_safe
4. long_fall_low
5. long_fall_high

I like the latter, it’s the only concise version that seems clear, and risk is implied by the new key.

3 could technically be long_falls_none but that makes no sense. :stuck_out_tongue:

again from my partner as I’m bouncing ideas off of her: “This is harder than it seems like it should be”.

The vertigo section you point at likely is not what gives the climbing grade. Knife like aretes like that, many people just “ride” them. Sections minutes later are technically more demanding. Wide angle action cam shots often greatly exaggerate, but the rating specified alone rules out a path in the OSM sense, this is a bolted sport climbing route.

So, highway=path has been removed from the whole way. Locals are welcome to split it into pieces an reapply path where it fits. I find it funny that people discussing a topic like this are fine with such trolling.

On location, rock was wet at the time, and I saw a chute below the path. Only the next day I learned, that behind the branches of bushes that took sight a deep drop existed. I was cautioning myself of the idea, that unstoppably sliding down compacted fine-gravel will hurt no matter how far whatever below.

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I’d say, this can indeed be easier, just tag


on nodes, exactly where the hazard is, and be done with.

This will of course run against some peoples opinion, that only signed hazards are to be mapped. Should we care?

I didn’t go look it up on OSM (and I’m not sure StC did either), it was just shared as a classic example of an “exposed” route. Trolling might be going a bit far.

My question was rhetorical about what a use_caution value could indicate.

That does seem like an adequate use of caution on your part though. :slight_smile:

That assumes that there is one specific area that is exposed, which isn’t always the case. hazard=deep_fall doesn’t seem to be a recognized value for that key and would only really cover the last two ratings. Do we just drop hazard tags every few meter for hundreds of meters?

I think a node solution would be appropriate in areas (and StC would agree based on discussions elsewhere) where in general a trail has no fall risk except for a very small portion of it. Similarly I could see this being used for a quick mantle or drop off of a ledge which would technically be T4 terrain but not worth rating an entire path at and creating a new segment for 2m of trail seems ridiculous.

Much of OSM is heavily vehicle orientated - smoothness is one key that keeps getting brought up but is ridiculous for hiking paths, any surface variance over 24cm is impassable? Hmm.

There are some existing keys that should either have shadow keys - hiking_smoothness, hiking_hazard, or just a separate section with hiking values and descriptions with guidance. The former is cleaner, the latter probably simpler.

I’d suggest starting a new thread on this since you seem to have some ideas about it!

@Hungerburg Someone else had a similar idea here.

I think the correct approach is to use a hazard=* tag. I’d quite like a systematic list of typical hazards for walkers (e.g., tides, quicksand, fastflowing river, fast rising river, loose rock, rock fall, serac fall, crevasses, cornice, avalanche, slippery when wet, exposed, risk of falling etc)

The hard part is coming up with a concise wording which is clear. I think the general values are useful to describe a path, and aside from airy_but_safe are more or less mirrored across parts of SAC (though I couldn’t draw the exact line at the higher ratings).

trivial = T1, short_falls = T2, long_falls_low = T3? T3-T4?, long_falls_high = T4-T6? T5-T6?

Having a separate key lets us tag with more granularity - say those examples where technique is T1 but exposure is T4, or a short scramble (T4-T6) which is technical enough to act as a barrier to someone without the technical skill but not long or exposed enough (T2-T3) to be fatal exposure.

The case of a trail which is T1 technique, but near a T3-T4 edge for a long time is a good casual use case - some people will be unafraid to hike it due to that exposure even though it is generally safe - it’s not quite a “hazard”. The example above is actually a good use case (values edited to keep up with evolution).