Fire magic under water

[cullynthedwarf]

Does any magic have any strange effects under water?

[Gastronomie]

All creatures gain fire resistance underwater.

[Mr.Spastic]

They way I run this is a bit more realistic. They fire instantly turns all of the water it touches(area of effect into steam. That immediately creates a pressure blast that deals 10d6 damage to everyone fully submersed in the water(depending on the size of the body). It basically means you shouldn't do it if your all underwater. I also triple the area of effect of thunder damgae spells and double the range of lightning damage.

[Unoriginal]

They way I run this is a bit more realistic. They fire instantly turns all of the water it touches(area of effect into steam. That immediately creates a pressure blast that deals 10d6 damage to everyone fully submersed in the water(depending on the size of the body). It basically means you shouldn't do it if your all underwater. I also triple the area of effect of thunder damgae spells and double the range of lightning damage.

Fire magic isn't realistic, same for all the "elemental evocation" stuff. You can cast Call Lightning underwater without it affecting the water around it.

[Mr.Spastic]

Fire magic isn't realistic, same for all the "elemental evocation" stuff. You can cast Call Lightning underwater without it affecting the water around it.

Um, yeah. That wasn't the point. I was just saying how I do it in my own games. You know, to give some fun suggestions for house rules.

[ImproperJustice]

I mean sure. Maybe it boils the fishies instead of a big gout of fire.

Also, despite Hollywood phsyics, Lightning would actually just get dispersed (mostly harmlessly) in all directions in a large body of water, if we were applying real physics, but who says magic has to follow physics.

[Ivor_The_Mad]

Depending on the temperature of the fire spell changes its effectiveness. There is a point at which the fire is able to pull O2 from the water and use that for fuel. It's not that hard either. I don't think that it would create a pressure blast but it would considerably heat up the water around.

I typically don't over think it and just rule it the same unless it is a cantrip to 1st level spell then it has no effect. And none of them can light any of them on fire.

[Potato_Priest]

They way I run this is a bit more realistic. They fire instantly turns all of the water it touches(area of effect into steam. That immediately creates a pressure blast that deals 10d6 damage to everyone fully submersed in the water(depending on the size of the body). It basically means you shouldn't do it if your all underwater. I also triple the area of effect of thunder damgae spells and double the range of lightning damage.

Do you do this for all fire spells?

[JNAProductions]

Do you do this for all fire spells?

If so, Firebolt is a little harsh underwater.

[Potato_Priest]

If so, Firebolt is a little harsh underwater.

My thoughts exactly. Burning hands as well.

[Icecaster]

Well, as far as "any magic," there's also the consideration of cold spells. Would cone of cold freeze everything in its area? If so, could that trap monsters? Hmmmm...

As for fire magic, I would probably rule that the fire expands, briefly displacing water and dealing fire damage to the creatures (who have resistance), before returning to its former place, maybe boiling a small amount of water, creating some bubbles. In the case of something like wall of fire, though, I'd describe the same effect, just perpetuated.

[kamap]

You could add something but that would be a houserule.
Magic doesn't change much under water, except maybe the settings things on fire but that aren't worn etc. It might flare up and then just get doused.

[LudicSavant]

All creatures gain fire resistance underwater.

Gastronomie is correct. Specifically, this rule is found on Pg198 of the PHB.