A question about the mechanics of a fireball under water

[lonodor88]

According to the rules, spells with the fire descriptor cannot be used underwater, I understood that. But will a fireball work if you throw it into the water while standing on the bridge?

[Tridus]

It'd work on anything floating at the surface. But after that it's underwater and so "it can't be used underwater" applies.

[Easl]

If you want to hit the underwater beastie with thrown fire, you can do that in two easy steps.

Step 1: call over your fire kineticist friend
Step 2: have them do it

[Finoan]

There is also the Undine feat Steam Spell.

[lonodor88]

The following is written - "You can't cast fire spells or use actions with the fire trait underwater. As normal for how traits work, any part of the effect that's unrelated to fire still works. For example, an attack with a
flaming battleaxe could still deal its physical damage, just not its fire damage." Cast. But nowhere have I found that it is impossible to create a fireball on a bridge and launch it into the water.I understand that this implies indirectly, but maybe there are specific examples of other effects?

[Tridus]

lonodor88 wrote:

The following is written - "You can't cast fire spells or use actions with the fire trait underwater. As normal for how traits work, any part of the effect that's unrelated to fire still works. For example, an attack with a

flaming battleaxe could still deal its physical damage, just not its fire damage." Cast. But nowhere have I found that it is impossible to create a fireball on a bridge and launch it into the water.I understand that this implies indirectly, but maybe there are specific examples of other effects?

The rules don't tend to spell this out because they're not written as a technical manual where anything not explicitly stated must work because it's not explicitly banned.

But if the spell/effect doesn't work if you cast it underwater, it probably also doesn't work if you cast it above water and try to launch it into the water. You've ended up in the same place: the spell is underwater. What's the justification for why it works underwater in one case and not the other aside from "the rules don't explicitly prevent this?"

[Easl]

lonodor88 wrote:

But nowhere have I found that it is impossible to create a fireball on a bridge and launch it into the water.I understand that this implies indirectly, but maybe there are specific examples of other effects?

See "Aquatic combat." https://2e.aonprd.com/Rules.aspx?ID=2438

I would guess that most GMs would use the last bullet to say no to what you're suggesting: At the GM's discretion, some ground-based actions might not work underwater or while floating.

[Nelzy]

Easl wrote:

lonodor88 wrote:

But nowhere have I found that it is impossible to create a fireball on a bridge and launch it into the water.I understand that this implies indirectly, but maybe there are specific examples of other effects?

See "Aquatic combat." https://2e.aonprd.com/Rules.aspx?ID=2438

I would guess that most GMs would use the last bullet to say no to what you're suggesting: At the GM's discretion, some ground-based actions might not work underwater or while floating.

Firstly im not sure how i stand on this topic.

but have 2 things to point out.

why did they bother with saying that both ranged attack "used by an underwater creature or against an underwater target" and not use the same wording when talking about fire traits and spells.

Also why would they bother with "You gain resistance 5 to acid and fire."

if there is no way to cast fire traits things into the water?

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Kinda unrelated also, Fireball is not a projectile in its description in pf2 its just a targeted blast that appears at the target location.

[Errenor]

Nelzy wrote:

Also why would they bother with "You gain resistance 5 to acid and fire."

if there is no way to cast fire traits things into the water?

Yes, at least two were mentioned above. Also hypothetically effects could exist which don't have fire trait but do fire damage. High temperatures aren't forbidden under water, just open fire. And damage from high temperature is represented by fire damage in the game.

[NorrKnekten]

There are a few things one probably should note, First is that First Edition actually did explicitly state that water blocks line of effect for all fire effects.

Second is one would expect wall of water to block all fireeffects, but it doesn't, Only counteracts.
We do have a few things that can deal fire-damage without being firetraited, Shadowblast for example. I also have memories of poisons/curses that deal firedamage and those wouldn't be removed underwater.

Overall, this is a really weird one to consider.

[Finoan]

Nelzy wrote:

Also why would they bother with "You gain resistance 5 to acid and fire."

if there is no way to cast fire traits things into the water?

That entire list of bullet points is for battles that happen 'in water' as well as 'underwater'.

The acid and fire resistance is for when you are at the surface of the water - Combat while swimming or wading in deep water, but not underwater. At that point you gain the acid and fire resistance, but enemies can still use fire attacks against you above the water's surface.

[cavernshark]

NorrKnekten wrote:

There are a few things one probably should note, First is that First Edition actually did explicitly state that water blocks line of effect for all fire effects.

Second is one would expect wall of water to block all fireeffects, but it doesn't, Only counteracts.
We do have a few things that can deal fire-damage without being firetraited, Shadowblast for example. I also have memories of poisons/curses that deal firedamage and those wouldn't be removed underwater.

Overall, this is a really weird one to consider.

Tengu's Mariner's Fire ancestry feat allows the Tengu to cast Ignition underwater, but won't remove the 5 resistance the target will receive.

Blistering Invective is a spell which can do fire damage without having the fire trait. It does not have the Fire trait and is primarily mental spell with Auditory, Mental, Emotion, and Fear traits. It can be cast underwater and will apply Persistent Fire damage on all but a critical success from the target.

Under the rules for Assisted Recovery, a GM can decide that some things will "Automatically end the condition due to the type of help, such as healing that restores you to your maximum HP to end persistent bleed damage, or submerging yourself in a lake to end persistent fire damage," but this is an optional adjudication by a given GM. The 5 fire resist from being under water guards against any fire damage that can get through the usual restrictions and implications of fire underwater.

I think the intent is pretty clear that fire is meant to be mostly negated in a Water environment. There are some ways to get around that, and the resistance is in place for those instances.

For the specific question: if you detonate the fireball above the surface, I'd probably let it affect creatures in the water using the following rulings: if they are at the surface, I'd just give them the resistance; if they are submerged at all, I'd give them a +2 circumstance bonus to their saving throw due to Standard Cover in addition to the resistance, maybe going to +4 greater cover based on depth. If you detonate it under the water or at the water's surface directly, I'd probably rule it doesn't work.

This feels like the kind of thing that happens only occasionally in most campaigns (a GM might only have to deal with it once) or it'll happen all the time (you're in a heavily water/aquatic campaign), at which point if I'm your GM I'm probably asking why you picked Fireball in the first place over other options.

[Easl]

cavernshark wrote:

This feels like the kind of thing that happens only occasionally in most campaigns (a GM might only have to deal with it once) or it'll happen all the time (you're in a heavily water/aquatic campaign), at which point if I'm your GM I'm probably asking why you picked Fireball in the first place over other options.

Hopefully it's not terrible for the PC. If they're a prepared caster they can swap it out next day, while if they're a spontaneous caster they can use the slot for other spells until they next level up and can change their repertoire.