More granular lava damage rules

[Elysiume]

Lava is several times denser than water and 5-6 orders of magnitude more viscous than water. If one were to stumble into a pool of lava or magma, they're not going to sink like a stone, since they'd be sinking into stone. The rules, unfortunately, just offer the following:

Lava or magma deals 2d6 points of fire damage per round of exposure, except in the case of total immersion (such as when a character falls into the crater of an active volcano), which deals 20d6 points of fire damage per round.If someone were to step on lava, they wouldn't be totally immersed: it's just too dense and viscous. I'm looking for some alternate rules, since my group may be wandering near some lava in short order. If not for the serious risk that characters end up on the lava, I wouldn't bother, but the RAW has quite the gulf in the middle. 2d6 is pathetically low for trying to traverse lava, while 20d6 spells near-certain death at the levels they're at.

This will be for Pathfinder so some minutiae (mostly the way players could respond to or handle lava) will be different, but the base rules for lava/magma are near-identical.

I was thinking something like the following categories:

Minor exposure for 2d6, such as a rock falling into a lava pool that you're standing next to (reflex negates).
Moderate exposure for 6d6, such as having 1-2 limbs in contact when you're trying to run across it (acrobatics to succeed).
Major exposure for 8d6, such as having 3-4 limbs in contact because you failed that acrobatics check and went sprawling.
Extreme exposure for 10d6, such as being knocked out on top of lava so your entire body is in contact.
Immersion for 20d6, such as a fire-immune earth elemental grappling you into the lava.
Thoughts? Does anyone have house rules that they're fond of and would like to share?

e: please nobody suggest Fire and Brimstone, I've seen that joke play out far too many times in my search for alternate rules that I liked

[el minster]

What about rules about solidifying the lava?

[Elysiume]

What about rules about solidifying the lava?Do you mean like casting Create Water atop the lava to try to flash-harden the surface layer, or more concretely defining how far someone would sink into it?

[el minster]

Create water would do it but would also potentially creat a dangerous cloud of superheated steam.

[Ashtagon]

If an unprotected or barely-protected person were to step on lava, the disturbance would cause the lava to be "invigorated". Someone running or jumping can expect the ground to give way and fall. They might briefly submerge, but would quickly bob to the surface. With sufficient heat protection and the heat-resistant equivalent of snowshoes, a person might be able to walk slowly on the surface. At a very least, Balance checks should be called for, with severe penalties for any kind of movement, or any kind of nearby spillage of flammable material.

Also relevant: https://www.youtube.com/watch?v=KeSet41brAA

[Gusmo]

1d6 or 2d6 environmental damage per round based on proximity, in effect at all times in addition to touching rules. For running across, I would say the lava does 1d6 damage per square of movement it costs to get across. The terrain itself is difficult, and perhaps visibility will be poor, which means 4 squares of movement and 4d6 damage per tile to get across. Skill check required in each square. This means people who are able to get across quicker because they can negotiate it better save themselves damage. Perhaps an epic character, if they also were able to eliminate the difficult terrain aspect of movement, could make a skill check sufficiently high that they even take no damage (other than the environmental damage) from being so light on their feet. From there you could add +5d6, +10d6, or more additional penalties if someone trips or whatever.

[el minster]

1d6 or 2d6 environmental damage per round based on proximity, in effect at all times in addition to touching rules. For running across, I would say the lava does 1d6 damage per square of movement it costs to get across. The terrain itself is difficult, and perhaps visibility will be poor, which means 4 squares of movement and 4d6 damage per tile to get across. Skill check required in each square. This means people who are able to get across quicker because they can negotiate it better save themselves damage. Perhaps an epic character, if they also were able to eliminate the difficult terrain aspect of movement, could make a skill check sufficiently high that they even take no damage (other than the environmental damage) from being so light on their feet. From there you could add +5d6, +10d6, or more additional penalties if someone trips or whatever.

Isn't there a magic item in Cadv that lets you walk on water?

[Gusmo]

Isn't there a magic item in Cadv that lets you walk on water?

Regardless of the source, any such walk on water effect would be a reasonable way to remove the difficult terrain aspect.

[Fizban]

2d6 is pathetically low for trying to traverse lava,
It also continues after they break contact, but yes it's a bit odd that liquid immersion rules only recognize splash and dunk tank.
while 20d6 spells near-certain death at the levels they're at.

Minor exposure for 2d6, such as a rock falling into a lava pool that you're standing next to (reflex negates).
Seems a bit harsh. If it's so viscous you could potentially walk on it, it should hardly splash either.

Moderate exposure for 6d6, such as having 1-2 limbs in contact when you're trying to run across it (acrobatics to succeed).
Major exposure for 8d6, such as having 3-4 limbs in contact because you failed that acrobatics check and went sprawling.
Extreme exposure for 10d6, such as being knocked out on top of lava so your entire body is in contact.
Immersion for 20d6, such as a fire-immune earth elemental grappling you into the lava.
Too granular if you ask me. I'd go with the 2d6 for a brush or intentional splash, 4d6 if you stand on it, 10d6 for partial immersion/broadside contact, and then of course the 20d6 if you get pulled under (or thrown/dropped in hard enough). And remember that the extra 1d3 rounds means those are actually a lot more if you don't have the resistance.

I was expecting more question regarding sinking- to which I was going to respond with the Rock to Mud spell or terrain rules, but it turns out they don't have any sink times aside from the 'ol fantasy quicksand.

Possibly more relevant than exactly how many rounds the PCs can survive without magical protection, is how you're going to handle damage to their gear. Boiling water doesn't destroy clothing, but I would expect anything that touches the lava to take the same damage and/or burst into flame (which will likely destroy it in 1 round regardless, as clothing has next to no hit points). And magic items take damage the same way.

[Aotrs Commander]

A qucik google suggests the the actual result of jumping into lava is that you would float on the surface in terms of density, but as the temperature is 1200-2000ºF (putting into D&D terms, 700-1200ºC for the rest of us for who farenheit is a foriegn land), the places I looked at (https://digg.com/2017/jump-into-lava) suggest you would actaully kind of explode instead (likening it to what happens if you throw an ice cube into a frying pan).

So you die all the same, just in a slightly different way...

[Nifft]

There's at least one comprehensive rules supplement on the topic: http://www.scratchfactory.com/Resources/LavaBanners/LavaRules.pdf

It's got some very prestigious reviewers (Gary Gygax, Wil Wheaton, Ed Greenwood, Scott Rouse, and Robin D. Laws to name a few names).

[Remuko]

There's at least one comprehensive rules supplement on the topic: http://www.scratchfactory.com/Resources/LavaBanners/LavaRules.pdf

It's got some very prestigious reviewers (Gary Gygax, Wil Wheaton, Ed Greenwood, Scott Rouse, and Robin D. Laws to name a few names).

im surprised it took this long for this to be posted.

[ExLibrisMortis]

From a simulationist perspective, if you're allowing low-to-mid level people without magical protection to touch lava and live, something's probably gone wrong--lava is very, very hot, and unlike other things that are that hot (like kilns and blast furnaces), there's a lot of hot stuff exposed to the air, heating up a big area around the lava. So instead of making granular lava damage rules, I'd suggest starting the damage further out, making the surroundings of lava dangerous.

I'd probably use elemental plane of fire traits (Manual of the Planes page 75) around significant masses of lava. For example, if you're within x feet of an x-foot radius pool of lava, you are in a fire-dominant area, taking 3d10 damage per round, affecting vision, and so on. That way, big volcanoes are hard to approach close enough to see the lava, but a small vent might be reasonably safe (and dwarves can use them as fuel-free forges, as long as they use 5' tongs to handle anything in the forge). Then, actually touching lava simply deals additional damage per round (d10s, to match the fire trait), which you can increment fairly aggressively: 6d10 for a touch smaller than a hand, 10d10 for a touch greater than a hand but smaller than a torso, and 15d10 (~23d6 equivalent) for a touch greater than a torso, also known as immersion. You can also use "searing fire" (fire that bypasses resistance), but that's definitely a magical thing, so that may be better suited for volcanoes with strong magical associations.

If you want, you can also use the Sandstorm heat danger rules, which expand on the MotP rules a bit (metal armour is affected as if by heat metal, potions boil off, lamp oil ignites, and so on), and also defines additional temperature bands (all cooler than fire-dominant, of course) and heat protection required for each. You could have some bands of unearthly and extreme heat around the burning heat from the lava.


im surprised it took this long for this to be posted.
Probably because the OP already asked people not to.

[Nifft]

Probably because the OP already asked people not to.
... by editing that in after the post in question?

Not really a valid argument.

--- ----- ---

@Elysiume -- You might look at some rules which scale damage on different fire sizes (https://www.d20srd.org/srd/psionic/powers/controlFlames.htm) and adapt that to lava (somehow).

You might also look at bludgeoning damage, because rock is dense and heavy even when it's liquid. If you get hit by a chuck of liquid magma, you're getting bludgeoned in addition to being cooked alive.

[ExLibrisMortis]

... by editing that in after the post in question?

Not really a valid argument.
Not valid? Why wouldn't it be valid? Look at the editing time--it was added 9 minutes after posting. You just missed it because it's at the bottom of the post, I guess. It's hardly a big deal either way, but I don't see why you have to argue the validity of the request.

[Elysiume]

For some more specific notes, the players will likely be levels 6-8 when they hit the lava. This is part of (spoilers for a PF adventure path)
the Emerald Spire, which includes the ability to blindly teleport to later floors which are otherwise increase by level as you go deeper. One of those offers a tiny safe platform surrounded by lava, including enemies that may try to knock players into the lava.Because of that, the players could end up there at both varying levels and varying degrees of preparation.

There's another important note for the specific area, but I'm going to disregard it for this post:
The magics of the spire regulate the temperature in the area, so it's always 100F outside of the lava.

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Thanks for all the feedback; distilling it down:

Lava should be difficult terrain and likely difficult to see around.
Being anywhere close to lava is going to be miserable before you even get in contact with the lava.
Too many tiers for lava damage.
Damage to items is very important, especially magic items.


While I like the idea of having a lot of item-specific interactions, I'm worried about it making things too complicated. Same reason I put together size- and velocity-based falling damage rules that I've never actually used.

The fire-dominant trait is interesting because it's actually quite a bit worse than mild contact with lava (avg. 16.5 vs. 7) and even comparable to the damage I'm planning to use for moderate contact (avg. 14). I really like the heat causing ripples and mirages in the air -- maybe something like concealment for any creature that doesn't have a fire or fire-related subtype within 10' of lava?

So:

Being near lava:

Any enclosed space with lava has an ambient temperature of severe heat. Outdoor areas with exposed lava are treated as one temperature band lower than enclosed spaces.
Within 50' of lava in an enclosed space counts as extreme heat.
Within 10' of lava in an enclosed space counts as unearthly heat. Unprotected characters take 1d6 points of lethal damage and 1d4 points of nonlethal damage per round (no save). In addition, any character wearing or otherwise touching metal equipment is affected as if by heat metal, gradually ramping up to the 3rd round effect and remaining there as long as they remain in unearthly heat.
In addition to damage from heat, any character without a fire or fire-related subtype that is within 10' of lava (enclosed or otherwise) treats all targets as if they had concealment due to the shimmering mirages from heat.


Touching lava (not recommended):

Falling onto lava uses the rules for hard surfaces, not water.
Walking on lava is difficult terrain. Water walk or equivalent allows a character to ignore this effect, but they still incur damage.
Any effect that allows a character to hover slightly above lava (within 1') is counted as minor exposure.
Minor exposure such as brushing against lava deals 2d6 points of fire damage.
Moderate exposure such as standing on lava deals 4d6 points of fire damage.
Major exposure such as lying down on lava deals 10d6 points of fire damage.
Immersion deals 20d6 points of fire damage.

Damage from lava continues for 1d3 rounds after exposure ceases, but this additional damage is only half of that dealt during actual contact.

Equipment in direct contact with lava takes 4d6 damage per round with the same stickiness rules as a character. Unlike normal energy damage, this damage is not halved against objects due to the extreme heat of the lava.

A character affected by resist energy, protection from energy, or equivalent does not count damage to both their character and their equipment against the maximum reduction. If damage against both the character and their equipment is prevented, only the higher value is subtracted from the maximum.

[Fizban]

While I like the idea of having a lot of item-specific interactions, I'm worried about it making things too complicated. Same reason I put together size- and velocity-based falling damage rules that I've never actually used.
Not that complicated in the end- anything that isn't made of metal goes poof, metal goes "oh god oh god ow get me out!"

The fire-dominant trait is interesting because it's actually quite a bit worse than mild contact with lava (avg. 16.5 vs. 7) and even comparable to the damage I'm planning to use for moderate contact (avg. 14). I really like the heat causing ripples and mirages in the air -- maybe something like concealment for any creature that doesn't have a fire or fire-related subtype within 10' of lava?
Note that heat shimmers are caused by changes in air refraction due to temperature, and usually require quite a distance. I'm pretty sure the effect is greater if you're in air that is of a different temperature- but at close range all at the same heat I wouldn't expect significant effects. Smoke on the other hand. . .


Within 50' of lava in an enclosed space counts as extreme heat.
Within 10' of lava in an enclosed space counts as unearthly heat. Unprotected characters take 1d6 points of lethal damage and 1d4 points of nonlethal damage per round (no save). In addition, any character wearing or otherwise touching metal equipment is affected as if by heat metal, gradually ramping up to the 3rd round effect and remaining there as long as they remain in unearthly heat.
If those are based on actual recorded temperatures at those ranges, I guess that's how it goes. But note the mechanical effect that any normal person (normal people have 1-4 hit points) who comes within 10' of lava pretty much instantly falls unconscious and dies. Normally continuous effects tend to activate when you enter them and then at the start of each turn after that- you can reduce this problem by stipulating that the damage only occurs at the start of your turn when you remain in the area (and of course that creatures entering the area feel heat so bad they know they need to leave before they run out of movement).

Granted, I'm still not sure normal people should instantly faint in 6 seconds of 180 degree air, but I've never experienced it so maybe it is that bad, and this is full body saturation- and there's a similar hit point abstraction problem in getting splashed with boiling water or any number of substances (or catching on fire) that in real life would certainly put you on the ground screaming but probably wouldn't immediately send you into shock. So its probably fine?


Touching lava (not recommended):
Sounds good.

Equipment in direct contact with lava takes 4d6 damage per round with the same stickiness rules as a character. Unlike normal energy damage, this damage is not halved against objects due to the extreme heat of the lava.
Half of ~14 is still 7, enough to incinerate cloth and leather, damage wood, and fail to instantly melt steel (prolonged contact will eventually roll the 22 required to damage steel). Unless you want their metal to melt instantly, as ~14 minus 10 is 4, so that's daggers and smaller destroyed and even a longsword nearly at zero.

The annoying thing to track would normally be catching on fire since it can apply to the character and also every individual item. This can be simplified (albeit clumbsily) by only tracking one "on fire" effect for the whole character, so you roll a single d6 and that's the damage that the exposed items take- which exposed items should be a simple enough judgement. Having all items either take little or lots of damage is weird, but less cumbersome. Though one should also note that in the case of item damage, much like random treasure, many players might prefer the gambling tension of each item's individual roll, and resulting relief/despair that one particular item rolled low or high.

While its not explicit, I would say that the damage for flammable objects being on fire should bypass the 1/2 damage rule. A burning wooden shield/weapon would still need to roll 6's to take damage, but otherwise it deals nothing, and bypassing hardness means they're destroyed almost immediately.


A character affected by resist energy, protection from energy, or equivalent does not count damage to both their character and their equipment against the maximum reduction. If damage against both the character and their equipment is prevented, only the higher value is subtracted from the maximum.
I'd simply even further: "Any magical effect that prevents energy damage to a character completely protects their worn equipment at no cost, unless the character dies or rolls a natural 1 on a saving throw (see Items Surviving a Failed Saving Throw)." Then, if held items/weapons need to be protected: "A held or wielded item attacked or intentionally exposed is treated by the spell as if it were the character."

[Eldan]

Stone should be fine for a bit in lava, too. Probably some ceramics, too?

But yeah. I'd make some sort of "proximity to lava" chart. You take X damage per round if you are Y feet away from lava.

[Buufreak]

For an actual gaming example, though not in with the bulk of d20, I turn to breath of the wild. Part of the game takes place near and in an active volcano, where just approaching causes your inventory (and health of course) to spontaneously combust from the exposure to super heated air. And that starts to first occur near the base of the volcano, not anywhere close to the mouth or any active lava sites. Then, obviously, it increases in intensity as you climb higher and inevitably closer to the lava pools, requiring more and more protection until you are eventually a walking kiln (because if it can keep hot in it can also keep hot out).

How proximal are you wanting to get to actual lava, in game terms? Are you wanting players to actually traverse across it? Because as mentioned, within all reasoning of physics, they would explode due to rapid liquid boiling within their bodies, while the more carbony bits will combust. Endure elements isn't going to affect this at all, you'd need something more extreme, because the air is going to be well above what that spell can handle. And that's all before actually making contact with magma.

Perhaps the crafting of a new spell would be the best route. How are you when dealing with custom magics? Resist energy at 2nd spell slot, caster level 11 can absorb 30 points of fire damage, but blatantly calls out that it only soaks the damage and not any other potential side effects. I'd like to think something of 3rd or 4th level should manage to give all the appropriate effects to not instantly die from the heat and fire exposure.

[SirNibbles]

One thing to keep in mind is the possibility of lava falling on someone from above and immersing them, such as from a Transmute Rock to Lava spell, which specifically covers this scenario as well as some other lava scenarios:

"If transmute rock to lava is cast upon the ceiling of a cavern or tunnel, the lava falls to the floor and spreads out in a 15-foot-radius pool at a depth of approximately 1-1/2 feet. The rain of lava deals 2d6 points of fire damage and 1d6 points of bludgeoning damage to anyone caught directly beneath (Reflex half). In addition, creatures take 2d6 points of fire damage each round when they are caught in the area of the pool, then 1d6 points of fire damage for 1d3 rounds after they escape." - Complete Arcane, page 127

However, being completely covered in molten rock should probably deal more than 2d6 fire damage.

EDIT: Fizban has pointed out that Transmute Rock to Lava was updated. See Spell Compendium, page 222 for the most accurate rulings on how lava behaves in regards to the spell.

[Ashtagon]

I'd say if trying to walk on lava, there should be a Balance check (DC = distance moved in feet). Failure results in falling prone as the lava surface experiences a small rupture from the pressure stress. Creatures that are essentially made of fire (fire elementals, mostly; this does not include azers and the like) do not need to make these checks to avoid falling prone. Creatures that have fire immunity but are essentially solid (eg fire giants, azers) do need to make these checks, although they don't suffer any particular penalty beyond falling prone.

(Yes, that Balance DC gets real high real fast; running on lava should be pretty much impossible)

----

Another issue that hasn't been touched on yet is that lava that makes contact with sea water will form hydrochloric acid vapour, which has caused a surprisingly large number of deaths among people who thought they were safe.

[Fizban]

One thing to keep in mind is the possibility of lava falling on someone from above and immersing them, such as from a Transmute Rock to Lava spell, which specifically covers this scenario as well as some other lava scenarios:

"If transmute rock to lava is cast upon the ceiling of a cavern or tunnel, the lava falls to the floor and spreads out in a 15-foot-radius pool at a depth of approximately 1-1/2 feet. The rain of lava deals 2d6 points of fire damage and 1d6 points of bludgeoning damage to anyone caught directly beneath (Reflex half). In addition, creatures take 2d6 points of fire damage each round when they are caught in the area of the pool, then 1d6 points of fire damage for 1d3 rounds after they escape." - Complete Arcane, page 127

However, being completely covered in molten rock should probably deal more than 2d6 fire damage.
Amusingly, that's less damage than the mud from Transmute Rock to Mud- which deals 8d6 if cast over someone's head.

Transmute Rock to Lava also has a Spell Compendium update which increases the ceiling-drop-spread pool damage to 10d6 per round of standing in it, though not the ceiling drop damage- and being a 9th level spell this is one buff I don't massively disagree with. Scalding Mud from Sandstorm does 5d6 if you're "mired" or 10d6 if you're submerged.