Could cloudkill be dispersed by a thunderwave blast? The spell indicates a "strong wind", however since thunderwave creates a blast that even moves objects, could it also move the fog? I ruled no in a recent game, but I wanted to see what others think.
RAW? I don't know, but given that the Gust cantrip exists, I would 100% allow a player to expend a 1st level spell to disperse a portion of the Cloudkill.
However, Cloudkill continues to move every round, so the gap would probably be temporary.
If you think about it realistically, just sound wouldn't disperse a gas, but sound also doesn't push objects 10 feet. That seems more like a shockwave which certainly could disperse a gas.
Now mechanically, it depends on the DM. If they consider a shockwave as a wind or the cloudkill as an object, then possibly.
Could cloudkill be dispersed by a thunderwave blast? The spell indicates a "strong wind", however since thunderwave creates a blast that even moves objects, could it also move the fog? I ruled no in a recent game, but I wanted to see what others think.
Thunderwave does not actually indicate a strong wind. It indicates a 'thunderous force.' The damage type is even 'thunder' rather than 'force,' i.e sound.
As such it does not actually seem to be able to disburse the cloud. If the cloud counts as an object (not a given) it may be able to move it though.
“Force” damage is just generic magic damage. It has no relation to force as a physical quantity.
Thunder damage strong enough to knock creatures down and push objects away, as DxJxC said, is a shockwave. I don’t do fluid dynamics for a living, so I encourage anyone with more physics education than I have to correct me, but my gut feeling is that the cloud would just be part of the medium the wave travels through; i.e. it would move locally but not go anywhere else.
“Force” damage is just generic magic damage. It has no relation to force as a physical quantity.
Thunder damage strong enough to knock creatures down and push objects away, as DxJxC said, is a shockwave. I don’t do fluid dynamics for a living, so I encourage anyone with more physics education than I have to correct me, but my gut feeling is that the cloud would just be part of the medium the wave travels through; i.e. it would move locally but not go anywhere else.
It's also magic, lest we forget - and whatever the difference is between bludgeoning and thunder, it deals thunder, not bludgeoning. We need to be careful what assumptions we apply, and be aware we're assuming them for however we houserule.
I would rule that cloudkill is made up of an incredibly large number of incredibly small objects suspended in space, exactly like a cloud of smoke or ash or flour (cloudkill is fog, so technically it's made of drops of liquid, not tiny solids). Since Thunderwave moves objects, I would let it move all of the Cloudkill objects within range. Due to the rules text of Cloudkill, I would make the cloud sticky with respect to itself, so moving part of it moves all of it, much like if you were exerting magnetism on a magnetic cloud (such as a bunch of iron filings suspended in oil) - Cloudkill should maintain its shape, in general.
Thanks everyone! So, basically, it's a wonky situation that doesn't really have a good answer. I think for next time, I will allow Thunderwave to move the fog away 10ft from the caster of Thunderwave, but not disperse it. Though, even if that happened, in the scenario, Cloudkill's fog would have just moved back into the space of the caster of Thunderwave a few turns later, so luckily it would not have changed our battle much.
Thunder damage strong enough to knock creatures down and push objects away, as DxJxC said, is a shockwave. I don’t do fluid dynamics for a living, so I encourage anyone with more physics education than I have to correct me, but my gut feeling is that the cloud would just be part of the medium the wave travels through; i.e. it would move locally but not go anywhere else.
You'd be right about a sound wave not disturbing the medium it moves through, but shockwaves do. Shockwaves basically create a shell of compressed air as they move out, leaving a low pressure zone behind them. Between the shockwave losing more energy along the ground than air and the fact that their cause usually also makes heat is why air rushes in from under the shockwave, lifting it and making the classic mushroom cloud shape large explosions have.
There are a number of spells available that actually specify the generation of winds, but they are usually niche and rarely selected let alone actually used.
giving thunder wave features that other spells outright are designed to do makes those spell choices even less likely to be chosen and buffs thunder wave quite a bit.
Gust of wind is a level 2 concentration spell that seems to do what you want, though there are higher level spells that can also be used.
If I were DMing a game where it came up then I'd allow it. After all, if it's enough explosive force to knock a person/creature back 10 feet, then it must be able to move (or at least halt the advance of) gas.
Which is why, as Adversatrix pointed out, this concept is a wonky situation without a really good answer. If a player had tried to use thunderwave against a cloudkill spell, I'm not sure if I personally would allow it to push the poisonous gas back. Part of the verbiage from the thunderwave spell states the following:
In addition, unsecured objects that are completely within the area of effect are automatically pushed 10 feet away from you by the spell's effect
The way that I read this line in the context of this situation:
The cloudkill spell is a spell and not an object that would be capable of being pushed by the shockwave being created by a thunderwave spell.
Even if I were to consider the poisonous fog as an actual object, it's still a 20-foot radius sphere in size. These dimension would not be completely within the 15-foot cube being affected by the thunderwave spell, so it would not be pushed away.
Cloudkill is a 5th-level spell, which should not be so easily affected by a 1st-level spell. Understandably, gust of wind is only a 2nd-level, but it specifically states that part of its design is to blow/disperse fog away.
Other spells exist that are designed to counter/negate cloudkill and other similar spells; such as gust of wind.
Appreciate the inventiveness of the players, and I even respect the logic that quindraco and some of the other posters presented in favor of allowing this situation to work. Just not sure if I would have allowed it myself either, even if it was just a matter of moving the cloudkill back by 10 feet for a round or two.
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Could cloudkill be dispersed by a thunderwave blast? The spell indicates a "strong wind", however since thunderwave creates a blast that even moves objects, could it also move the fog? I ruled no in a recent game, but I wanted to see what others think.
I wouldn't let it *disperse* cloudkill, but I would let it *move* cloudkill.
RAW? I don't know, but given that the Gust cantrip exists, I would 100% allow a player to expend a 1st level spell to disperse a portion of the Cloudkill.
However, Cloudkill continues to move every round, so the gap would probably be temporary.
If you think about it realistically, just sound wouldn't disperse a gas, but sound also doesn't push objects 10 feet. That seems more like a shockwave which certainly could disperse a gas.
Now mechanically, it depends on the DM. If they consider a shockwave as a wind or the cloudkill as an object, then possibly.
“Force” damage is just generic magic damage. It has no relation to force as a physical quantity.
Thunder damage strong enough to knock creatures down and push objects away, as DxJxC said, is a shockwave. I don’t do fluid dynamics for a living, so I encourage anyone with more physics education than I have to correct me, but my gut feeling is that the cloud would just be part of the medium the wave travels through; i.e. it would move locally but not go anywhere else.
It's also magic, lest we forget - and whatever the difference is between bludgeoning and thunder, it deals thunder, not bludgeoning. We need to be careful what assumptions we apply, and be aware we're assuming them for however we houserule.
I would rule that cloudkill is made up of an incredibly large number of incredibly small objects suspended in space, exactly like a cloud of smoke or ash or flour (cloudkill is fog, so technically it's made of drops of liquid, not tiny solids). Since Thunderwave moves objects, I would let it move all of the Cloudkill objects within range. Due to the rules text of Cloudkill, I would make the cloud sticky with respect to itself, so moving part of it moves all of it, much like if you were exerting magnetism on a magnetic cloud (such as a bunch of iron filings suspended in oil) - Cloudkill should maintain its shape, in general.
Thanks everyone! So, basically, it's a wonky situation that doesn't really have a good answer. I think for next time, I will allow Thunderwave to move the fog away 10ft from the caster of Thunderwave, but not disperse it. Though, even if that happened, in the scenario, Cloudkill's fog would have just moved back into the space of the caster of Thunderwave a few turns later, so luckily it would not have changed our battle much.
You'd be right about a sound wave not disturbing the medium it moves through, but shockwaves do. Shockwaves basically create a shell of compressed air as they move out, leaving a low pressure zone behind them. Between the shockwave losing more energy along the ground than air and the fact that their cause usually also makes heat is why air rushes in from under the shockwave, lifting it and making the classic mushroom cloud shape large explosions have.
There are a number of spells available that actually specify the generation of winds, but they are usually niche and rarely selected let alone actually used.
giving thunder wave features that other spells outright are designed to do makes those spell choices even less likely to be chosen and buffs thunder wave quite a bit.
Gust of wind is a level 2 concentration spell that seems to do what you want, though there are higher level spells that can also be used.
If I were DMing a game where it came up then I'd allow it. After all, if it's enough explosive force to knock a person/creature back 10 feet, then it must be able to move (or at least halt the advance of) gas.
Which is why, as Adversatrix pointed out, this concept is a wonky situation without a really good answer. If a player had tried to use thunderwave against a cloudkill spell, I'm not sure if I personally would allow it to push the poisonous gas back. Part of the verbiage from the thunderwave spell states the following:
The way that I read this line in the context of this situation:
Appreciate the inventiveness of the players, and I even respect the logic that quindraco and some of the other posters presented in favor of allowing this situation to work. Just not sure if I would have allowed it myself either, even if it was just a matter of moving the cloudkill back by 10 feet for a round or two.