Your fireball has melted 2" of stone. Now what?

[Vahktang]

So, a 10 dice fireball, average damage, will melt 2"+ of stone in an average corridor.
Now what?
How do you cross melted stone?
Does it instantly harden again?
And the ceiling drips molten rock.
A save to avoid it?
Or 'it's magic Vahktang. Don't worry about it.'?

Reason why I am asking is that I am thinking of a room with support beams. Big explosive spells = roof false down, so our heroes must use personal weapons/personal spells vs the many, many bad guys.

 

[RangerWickett]

So, a 10 dice fireball, average damage, will melt 2"+ of stone in an average corridor.
Now what?
How do you cross melted stone?
Does it instantly harden again?
And the ceiling drips molten rock.
A save to avoid it?
Or 'it's magic Vahktang. Don't worry about it.'?

Reason why I am asking is that I am thinking of a room with support beams. Big explosive spells = roof false down, so our heroes must use personal weapons/personal spells vs the many, many bad guys.

http://www.d20srd.org/srd/exploration.htm#breakingAndEntering

Average damage is 35. However, fire deals half damage to objects, so you're dealing 17. Stone has hardness 8, so you're dealing 9 damage. 9 damage 'destroys' about half an inch of stone. By the rules, we don't know what happens to destroyed stone. I'd assume it was just cracked and burned, so that if one were to try to smash it, it would be brittle and provide no resistance. I don't think it would actually melt the stone.

Against wooden supports, though, you'd 'destroy' slightly more than an inch of wood. It'd depend on the specific structure, but I'd say that might be enough to bring down some things.

 

[Jdvn1]

Against wooden supports, though, you'd 'destroy' slightly more than an inch of wood. It'd depend on the specific structure, but I'd say that might be enough to bring down some things.

... Which seems odd. Shouldn't it be an inch from all affected sides of the column, since it's an area affect spell? (meaning, at least, it'd be 2 inches thinner?)

 

[Mr. Draco]

Interesting observation...

From a physics standpoint, the damage to the stone would most likely be from thermal shock (the top layer suddenely heating and expanding while the stone beneath it remains cool) rather than melting, so I'd side with RangerWickett's interpretation. Don't let that stop you from telling your players that they've just melted the stone hallway though.

 

[catsclaw227]

... Which seems odd. Shouldn't it be an inch from all affected sides of the column, since it's an area affect spell? (meaning, at least, it'd be 2 inches thinner?)

This seems logical to me. I would judge [IMC] that the hardness ratings and the thickness damage done assumes a plane. If more than one side of an object in 3-d sapce was affected at the same intensity then they'de be equally affected as described in the book.

 

[MarkB]

Against wooden supports, though, you'd 'destroy' slightly more than an inch of wood. It'd depend on the specific structure, but I'd say that might be enough to bring down some things.

I'd tend to make it more than that, given the rules on object vulnerability.

Vulnerability to Certain Attacks

Certain attacks are especially successful against some objects. In such cases, attacks deal double their normal damage and may ignore the object’s hardness.

I'd consider any non-treated wooden object more vulnerable to fire, so either you wouldn't halve the base damage or you'd ignore the hardness - or both.

The former results in three inches of wood buring through, the latter nearly 2 inches. In combination, it'd take out three and a half inches.

... Which seems odd. Shouldn't it be an inch from all affected sides of the column, since it's an area affect spell? (meaning, at least, it'd be 2 inches thinner?)

As a Burst spell, fireball doesn't curve around objects - so the near side of the column grants the far side cover from the damage, unless it burns through.

 

[Corsair]

As a Burst spell, fireball doesn't curve around objects - so the near side of the column grants the far side cover from the damage, unless it burns through.

Area: 20-ft.-radius spread

 

[MarkB]

Area: 20-ft.-radius spread

well darnit, how'd I misremember that one?

 

[Goolpsy]

well... if you want something to collapse.... then just be sure there carrying part is thin and has a heavy thing above... then you don't need much to trigger your wanted effect of the ceiling collapsing

 

[Jack Simth]

You really want something to collapse on command?

Take a bunch of mud.

Cast Transmute Mud to Rock

Quarry the rock for building the thing you want to collapse.

When you want it to collapse, simply Dispel the Permanent Transmute Mud to Rock, and presto - it all falls apart (as it's now mud).

Mix real rocks in there for a proper cave in, of course....