Really seriously impassable mountain ranges

[Michael Thayne]

So you're GMing a low-tech (possibly fantasy) campaign where, for whatever reason, the impassability of a certain mountain range is a major plot-point. Maybe you're planning on having the PCs go through a certain mountain pass, or even under the mountains (like the Mines of Moria sequence in Fellowship of the Rings). Whatever the case, the one player declares they'd like to go over the mountains instead. The PCs can't fly or anything, but everyone has decent Climbing skills and one PC even has Survival (Mountains) at a high level. What's stopping them.

The x0.2 multiplier on travel speed doesn't seem too prohibitive given that lots of terrain gives x0.5 anyway. If the mountain pass was going to take a day to cross, perhaps avoiding it adds a day and a half to travel time. Unless the GM is keeping the PCs on a very tight schedule, that's a delay that can be absorbed, so to speak. Now, maybe the 0.2x multiplier already is supposed to take into account established trails, passes, etc. but if so, how do you handle avoiding those things? Do you require Climbing rolls? If so, how many Climbing rolls, and at what penalty? As a GM, I'd be very reluctant to say flat out "nope, you can't do it" unless the mountain is literally tall enough to require survival gear that hasn't been invented yet, but just having the mountain slow them down a bit feels too easy.

[Ulzgoroth]

If they're taking a path that runs up faces that have to be climbed rather than hiked, certainly they should be making Climbing rolls. Which incidentally also makes carrying luggage or even supplies become a problem fast, unless you've got some kind of bags of holding. (Or maybe giant spiders as pack animals.)

[Boge]

At a certain altitude, they can't breathe. If the goal is to get them to go through the mountain rather than over it, yeah, they can't breathe that high. There's nothing they can do about it. It's not an option at that point to go over.

Look at Mt Everest. People die up there every year. They're hiking with modern technology and have the best escorts possible and they still die. There are barriers in Gurps that the players should not be able to pass. They need to find another way. If they continue, you make it so hard on them that they fail, fall, possibly die. Maybe they need the Common Sense advantage?

[Michael Thayne]

Originally Posted by Ulzgoroth

If they're taking a path that runs up faces that have to be climbed rather than hiked, certainly they should be making Climbing rolls. Which incidentally also makes carrying luggage or even supplies become a problem fast, unless you've got some kind of bags of holding. (Or maybe giant spiders as pack animals.)

My sense is that this is probably not true for lots of mountains, which might have slopes of 15°, 20°, even 30°, but I don't think you're supposed to make climbing rolls util the slope is significantly more than that (40°?, 45°? more? I'm not sure, but I don't think 30° is climbing). Sure steeper slopes sometimes occur, but how often? And even or that 45° slope, if the slope is long it would be extremely tedious to require climbing rolls every 5 minutes. as RAW would have you do. So I'm left a bit puzzled as to how to handle it.

Originally Posted by Boge

At a certain altitude, they can't breathe. If the goal is to get them to go through the mountain rather than over it, yeah, they can't breathe that high. There's nothing they can do about it. It's not an option at that point to go over.

Look at Mt Everest. People die up there every year. They're hiking with modern technology and have the best escorts possible and they still die. There are barriers in Gurps that the players should not be able to pass. They need to find another way. If they continue, you make it so hard on them that they fail, fall, possibly die. Maybe they need the Common Sense advantage?

The Himalayas are not representative of most mountain ranges. Peaks high enough to make the air difficult to breathe are fairly rare outside Asia afaict.

[Astromancer]

Given that it's a fantasy world, have you considered the possibility that unnatural climate conditions could block the mountains?

I once had an Ice Demon ruling a mountain range and enforcing an eternal winter. Vast heaps of snow and unpredictable avalanches made the mountains uncrossable. Another time a powerful mage cast spells that caused unending violent storms over mountains he wanted to block. Tornado winds and constant lightning blasts as well as flash floods made the mountains a death trap. Vulcan ism, unusual geology like supersharp rocks that slice through any protection, or simply unnatural heights beyond the atmosphere, could also work.

[Aldric]

Low tech and possibly fantasy?

Things that can stop an expedition are time and supplies first. If they can't bring enough food to get to the other side, they starve before they get there. Could have the same problem with water in some cases.
Weather, storms can hit them, or just the cold.
Terrain, sometimes they might have to climb, they could fail and get injured or even die. Or get caught in a landslide (or snow).

And then you said fantasy? Giants and Dragons just to name a couple of things that could make a mountain range impassable.

[Anthony]

The overland travel numbers are merely typical numbers, you can set terrain to arbitrary difficulty levels, or just use heavy handed tactics like having a snowstorm hit when they try to cross (JRR Tolkien, Railroad GM). Truly impassible mountains are probably something exotic, but exotic is fine as long as it otherwise fits the setting. However, even for perfectly normal mountains, if you don't have accurate maps, it's likely that you'll run into seriously impassible areas where you have to backtrack and go around, which can multiply the time to cross.

Personally, I would just come up with a list of hazards of crossing the mountains (some of which might be living creatures), and if the PCs try to cross anyway, that's their decision and they get the consequences.

[mr beer]

Atrocious weather can render mountains effectively impassable. I mean sure, go ahead, but you need special clothing and equipment, plenty of highly calorific food and high levels of Navigation and Survival.

Modern mountaineers have to hunker down in howling blizzard conditions and wait it out. Have a week of that followed by a game of Find That Crevasse, that might change their minds.

[lwcamp]

Where I am (Washington state), the thing that makes our Cascades mountains impassible are the winter storms. There are established passes, but there's no way to get over them when a storm dumps a bunch of snow on them. In the summer, they are not much of a problem.

The Lewis and Clark expedition nearly starved to death trying to get over the Bitterroot mountains in winter (the Shoshone tried to warn them, but did they listen? Noooo.) This left them in such a weakened state that when they encountered the Nimiipuu (Nez Perce) they were nearly all murdered and there wouldn't have been anything they could have done about it - only the pleading of one Nimiipuu woman spared their lives.

Back before contact with European people, but after acquiring horses, the Columbia plateau Native Americans regularly crossed the Rockies to hunt bison in the great plains, and to return home. This trip was not particularly remarkable to them. I presume this was when winter storms were no longer a threat. So the highest mountains in North America are crossable in summer by TL 0 people with horses. If you want mountains that are actually uncrossable (or at least very dangerous to cross) you are probably looking at something higher and wilder and more rugged than the Rockies in Idaho, Wyoming, and Montana.

Luke

[dcarson]

Winter hiking with cold and fighting snow needs 50% more calories then the other seasons. So if the high mountains are perma snow their rations won't last as long as they figured.