D&D 5E Climbing and fighting on a mountain side

[Orchrist]

Hi all!
In a homebrew campaign are the 4 PC's going to climb a steep, VERY high mountain. They will climb in two groups of three persons tied together with 30 feet rope as I understand is normal for climbing, each group lead by a NPC familiar with the mountain.
I have read everything I can find on the subject but felt I needed to add some rules and would love your comments and suggestions

First of would I like to introduce some problems, in particular since one likely is going to climb in full plate (or lose a ton of AC). I consider that rolling 5 or better on a 1d100 would mean no bigger issues for the individual PC/NPC during the entire climb, but rolling less would mean falling and dangling in the rope and taking 1d6 bludgeoning damage, causing the remaining two climbers to make a STR check to see if they can hold the fallen. If not they all will fall/tumble down say 200 meter and need a CON save (15) to avoid dying (with death saves). The other team can climb down and help them but this event will set them all back some hours, risking getting caught on the mountain side by nightfall.

Secondly will they be attacked, likely by a swarm of goblins or similar. I consider running this as a platform game with a lot of rock shelves to stand on, jump between and climb/jump up/down to, still limited by the 30 feet rope unless they cut or untie it (I'll mount string to the bases of the minis). This is where things get a bit hairy and homebrewed:
Climbing up/down/sideways; just use RAW.
Jumping to a platform in same level: DC10 DEX (acrobatics) save for a good landing, or they will fall. Not prone, but down. Because ice and snow everywhere.
Jumping up is according to RAW; 3 + STR mod if 10 feet movement first, half if standing. If arms are used to heave oneself up can 1½ the persons height be added (my addition: only empty handed)
Jumping down to a platform: For a good landing roll 1d20 >= 20 - (DEX mod. + size of platform [1-3 sq.]). Add further 1 for each 5 feet the PC is jumping sideways too.
Moving/fighting on a platform: Roll 1d20 for each 5 feet moved due to rocks, ice and snow. They fall if rolling 1.
Falling while tied together means that the next one in the rope (or both, if the middle person falls) can't fight, until the fallen PC is climbing or standing again (next round).
If/when landing on a shelf during a fall roll DEX check (15) to not fall further.
If two persons are falling will all three fall, unless the remaining person standing is one of the local guides.

Would this work? I'd hate to mess up the next session by forgetting to take something into consideration.

 

[Stormonu]

How deadly do you want this to be?

I’d drop the d100 roll for the guy in plate. That’s just punishing the warrior. Let the fighter have nice things.

The “fall on roll of 1” is a Jenga tower of doom. Someone is eventually going to fall, and you’re going to be rolling a lot of dice (6 dice with a regular move; on average, someone is going to fall for every round of regular 30’ movement or every two rounds of 15’ movement). I’d probably simplify that to a single Athletics/Acrobatics check DC 10 IF the character moves faster than 1/2 speed; failure means the character falls prone on the ledge, but if the check is failed by 4 or more the fall is off the edge. Characters can then play the risks of moving cautiously and being safe or risk moving quickly.

Also, may want to consider Concentration/Athletics/Acrobatics checks if a character gets hit while climbing. PCs and monsters, so players can attempt tactics to knock enemies off the mountain. Be aware that PCs/enemies might use ranged weapons or area attacks from static positions to clear lanes before moving on.

If you want this to be a running battle, you’ll need to introduce some element that makes the PCs want to keep moving - falling rocks/avalanches, bend & corners that enemies can’t be seen around, cover, a moving goal to chase, crumbling paths ahead/behind characters, etc. Note on the crumbling path - you’ll want to keep in mind characters moving at half speed and give them a chance to mostly move at slow speed, as long as its constant motion and they have to only “speed up” less than three times to make it safely through the gauntlet.

 

[aco175]

If the group is being relatively safe and climbing with rope and moving half speed, I would let them climb with no checks needed. Once you start with checks, someone is falling. Falls should be minor to average to level with falls of 1d4x10ft for a few d6s each time. The point is to not kill them and just frustrate them and still have them want to climb.

There should be places along the route that they can reach and be more safe like ledges and ruins of a tower or such. Perhaps the goblins are launching balloon attacks off the ledge of an old ruined platform. There could be an old entrance into the mountain that has collapsed, but the ledge is still there. Some of the PCs will want to double more to get to safety and take the attacks of opportunity to get there. I would also think that attacking while climbing should be at disadvantage and PCs would want to get to any safety to prevent that.

You can also get some variant rules like trying to attack w/o disadvantage requires an Athletics or Acrobatics check with the possibility of falling some. If the penalty is death from falling, the benefit is not worth it. I might make the DC10 to give a decent chance for the benefit.

 

[AverageMojito]

First, it looks like a cool scene: ambushed while climbing a steepy snowy mountain. Here's my take on this.

I'd use the 5% chance you suggested (1 on a d20) as a "complication meter". Instead of stacking the odds against one character, I'd stack against the entire party. For every X feet/yards/minutes/hours they climb/spend, roll a d20. On a 1, add a complication. Next roll is a 1-2, then 1-3 etc. What's a complication? Whatever adds fun and tension to the scene.

I'm strongly against the whole "full plate treatment". We usually don't care at all what armor a character is using until they get their dream plate, and suddenly they suck at everything they used to do just fine. Let the armored tanks be. A plate has the same effect as a chainmail, disadvantage on stealth checks. Chances are everyone's backpacks are full of tools and junk that would make swimming, climbing and even running a real pain (you know, physics), yet we cast that aside everytime and choose to focus on the (not so) poor plate guy.

For the planned battle scene, I'd run it with as little checks as possible for movement. If I pictured it as a cinematic fight scene, that's how I'd want it to feel at the table!
Snow and rock and stuff should make everything difficult terrain, anyway, and the rope length is a limit of how far characters can go. I'd let the dirty play for the goblin ambush, not the mountain itself. The goblins can easily hide and move around with their bonus action, so they're gonna wreak havoc with ranged weapons and throw rocks to activate nasty little traps. I'd let the characters, player or non-player, affect the terrain to cause nasty things, not a failed climb check or a failed save. Play it cinematic! This is the time for light and mobile characters to shine, let them shine! Go with the flow of their (probably crazy) ideas of how they're closing the gap to reach the goblin duo pulling the lever under that big rock above their heads...

 

[AverageMojito]

If you want this to be a running battle, you’ll need to introduce some element that makes the PCs want to keep moving - falling rocks/avalanches, bend & corners that enemies can’t be seen around, cover, a moving goal to chase, crumbling paths ahead/behind characters, etc. Note on the crumbling path - you’ll want to keep in mind characters moving at half speed and give them a chance to mostly move at slow speed, as long as its constant motion and they have to only “speed up” less than three times to make it safely through the gauntlet.

This is a neat idea: constant movement, not nitro.

 

[Swarmkeeper]

Hi all!
In a homebrew campaign are the 4 PC's going to climb a steep, VERY high mountain. They will climb in two groups of three persons tied together with 30 feet rope as I understand is normal for climbing, each group lead by a NPC familiar with the mountain.
I have read everything I can find on the subject but felt I needed to add some rules and would love your comments and suggestions )

Cool and exciting challenge! Hope it goes well!

First of would I like to introduce some problems, in particular since one likely is going to climb in full plate (or lose a ton of AC). I consider that rolling 5 or better on a 1d100 would mean no bigger issues for the individual PC/NPC during the entire climb, but rolling less would mean falling and dangling in the rope and taking 1d6 bludgeoning damage, causing the remaining two climbers to make a STR check to see if they can hold the fallen. If not they all will fall/tumble down say 200 meter and need a CON save (15) to avoid dying (with death saves). The other team can climb down and help them but this event will set them all back some hours, risking getting caught on the mountain side by nightfall.

So here you are introducing new game mechanics that are likely unnecessary. At best they are adding to your workload to remember. At worst, they are potentially causing a disconnect between what the players know to be the Ability check rules and what you introduce at the table. I'd err on the side of consistency with the rules that are already established.

That said, ditch the d100 and simply go with - if there truly is a challenging circumstance such as wind, a section of the rock face that is crumbling, falling debris - a climbing check (PHB p182) with a low DC and/or advantage because they are tied together (Working Together PHB p175)
Also, falling 200 meters is pretty harsh. The rules (PHB p183) indicate that falling creatures suffer 1d6 bludgeoning damage for each 10 feet fallen (to a max of 20d6). If they are level 1, no death saves needed, they are dead by virtue of damage very likely being twice their max HP. Might want to rethink this part.

Secondly will they be attacked, likely by a swarm of goblins or similar. I consider running this as a platform game with a lot of rock shelves to stand on, jump between and climb/jump up/down to, still limited by the 30 feet rope unless they cut or untie it (I'll mount string to the bases of the minis). This is where things get a bit hairy and homebrewed:
Climbing up/down/sideways; just use RAW.
Jumping to a platform in same level: DC10 DEX (acrobatics) save for a good landing, or they will fall. Not prone, but down. Because ice and snow everywhere.

I think this would be best served by a check rather than a save. Not clear how you are differentiating prone vs down. Do you mean they fall from the platform down 200 meters? Probably too harsh (see above)

Jumping up is according to RAW; 3 + STR mod if 10 feet movement first, half if standing. If arms are used to heave oneself up can 1½ the persons height be added (my addition: only empty handed)

Sounds fine.

Jumping down to a platform: For a good landing roll 1d20 >= 20 - (DEX mod. + size of platform [1-3 sq.]). Add further 1 for each 5 feet the PC is jumping sideways too.
Moving/fighting on a platform: Roll 1d20 for each 5 feet moved due to rocks, ice and snow. They fall if rolling 1.

Again, another situation where you might just call for a Dexterity (Acrobatics) check with a DC established on the fly based on distance rather than trying for some more complicated method that will cost you time and brain power while in the midst of a battle.

Falling while tied together means that the next one in the rope (or both, if the middle person falls) can't fight, until the fallen PC is climbing or standing again (next round).

Can't fight is a bit harsh. Maybe instead: attacks are with Disadvantage until the dangling PC is secured.

If/when landing on a shelf during a fall roll DEX check (15) to not fall further.

Consider offering advantage if they are tied to another.

If two persons are falling will all three fall, unless the remaining person standing is one of the local guides.

Consider allowing for a Strength check to prevent remaining PC from falling after the other two.

Would this work? I'd hate to mess up the next session by forgetting to take something into consideration.

Sounds fun whatever you decide. Good luck!

 

[Laurefindel]

Also consider that a failed climbing check or saving throw does not have to equate falling.

In combat, it could mean having to choose between action OR bonus action next round, lost of concentration on a spell, losing ammunition, being forced to Dodge your next turn to steady yourself, disadvantage on next attack roll etc.

while climbing the mountain, it could represent loss of equipment/rations, minor injuries (hp loss), level of exhaustion, taking longer than expected etc.

somewhere in there, the chance of falling to your death should be real enough to cause tension in the narrative, but it shouldn’t be the only consequence

 

[iserith]

I don't think any new rules are needed to pull this off and, as others have stated, the random chance for the armored PC to fall isn't good because it doesn't allow for any meaningful choice except wear armor or take it off (or perhaps use a climber's kit to reduce falling distance).

Remember, climbing and jumping don't actually have any ability checks associated with them except in particular circumstances, such as attempting to climb a sheer surface, avoiding hazards, or cling to a surface while something is trying to knock you off. A rope is just going to make this relatively easy with no checks necessary just to climb. Jumping would only call for an ability check if trying to do a stunt or maybe jump a longer distance than normal, provided something in the environment is allowing for that possibility (a swinging rope, perhaps).

If the platforms are narrow or slippery, then this may call for a Dexterity (Acrobatics) check, but you should be aware that doing so for every 5 feet is basically a death sentence (depending on the size of the platform). I would also make this relevant only to Medium-sized characters or larger. Small PCs wouldn't have to make that check and this would mean the goblins don't either. Jumping into difficult terrain would call for a similar check (DC 10). In general, you may say that failing these checks means the PC loses whatever they are holding to grasp onto the platform to avoid falling. Or perhaps they fall to the next shelf down. Again, they'll be wise to bring climber's kits with them.

In short, no new rules are required here in my view. Just use the ones you have, applying them whenever the player declares an action that has an uncertain outcome and a meaningful consequence for failure.

 

[Brotton Goodfellow]

Assume the characters have prepared for such an arduous task so all their climbing gear is in good working order.

Don’t bother with checks if they are taking their time and climbing cautiously.

Do bother with checks if some sort of external threat shows up. Falling rocks, an unexpected storm, goblin arrows.

If a 1 is rolled for a check centred around climbing and not falling, the character is barely hanging on and the player must use their next turn to make another check/save. Failure means falling and taking damage, and the character having to make up for lost distance.

A failed roll that isn’t a 1 just means the character doesn’t make any meaningful progress up the mountain.

On the flip side, a natty 20 means the character can move its full speed OR move regular climbing speed and give an ally advantage on their next check/save roll.

Make sure every player has a ranged option for combat.

 

[Stormonu]

A side question - what magic does your group have access to that could affect this encounter? You’ll want to think about how to incorporate these effects should the party use them, without punishing them for having these abilities.

• Levitate/Fly/Wind Walk/Feather Fall
• Alter Self/Wild shape (into a flying/climbing creature)
• Guidance/Enhance Ability/Jump
• Misty Step/Dimension Door/Teleport
• Gust of Wind
• Move Earth
• Spider Climb
• Freedom of Movement/Pass Without Trace (avoiding difficult terrain)
• Thunderwave (the movement can be an automatic encounter ended by blowing goblins off the wall, for example)