I played only D&D 3.0 and 3.5 editions, but if similar, low-level spells exist in D&D 4.0 and Pathfidnder, please comment, I will probably make a transition to one of them anyway.

Is it possible to pour water into a lock, cast 0-level spell Ray of Frost, freeze the water and break the lock this way or is it sanctioned anywhere? I mean, that's like 12 secs per lock at max (1 round for pouring, 1 round for casting), so if wizard is in a hurry it's kinda cool way, although looks like a little power-gaming.

(Not to mention an easy way to escape from a locked cell. Even if dungeon is dry and a character is left for death there are always 0-level clerical spells like Create Water and such wizard-cleric duo is good to go.)

It's more powerful than Open/Close spell since it won't fail on locked doors. Sure, it won't open door for us, but will break a lock -- something Open/Close can't do -- and then we will open it manually like normal mortals do anyway.

Also, it deals d3 damage, but I don't think we can use only this roll against lock DR, because frozen water is adding way more to this. There's also a question, how much water can you freeze with d3 cold damage?

Damn, I love such low-level hacking ;)

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    \$\begingroup\$ In real life, when you are trying to open/break a lock, does having frozen water inside the lock really help? In what way? \$\endgroup\$
    – enkryptor
    Commented Dec 1, 2016 at 16:19

7 Answers 7


I would say no, for several reasons:

Ray of Frost on the PFSRD.

  1. Ray of Frost does not freeze things, by RAW. There are spells that specifically say that they cause certain elemental effects (for example, Fireball specifically says that it "sets fire to combustibles") but Ray of Frost is not one of them. While it might be able to cool water or make a very small amount of ice, I doubt that Ray of Frost would be able to freeze enough water fast enough to break a lock.

  2. Actually making the water stay in the lock is non-trivial. If you have some way of keeping the water from spilling out of the keyholes, then this isn't as much of a problem, but I don't think much water will actually stay in the lock after you've poured it in.

  3. From a balance perspective, allowing an easy way to break open nonmagical, traditional locks using two 0-level spells is kind of cheesy, and Knock is 2nd level. I might be comfortable with players using a 1st level spell creatively this way, and definitely if they can creatively use a 2nd level spell for this kind of effect, but I think that using 0-level spells for a 2nd level effect is pushing it. I realize that Knock does more than just open nonmagical locks, but there isn't anything below 2nd level that can open locks, so I feel like that's a good baseline for this effect.

  4. I'm not sure this would actually work, at least not in a reasonable amount of time. While you could certainly make a lock stop working by freezing water in it, breaking the lock entirely requires much more pressure than ice can reasonably exert. I find it more likely that the iron or steel that most locks are made of would just force the ice out of the keyholes or into other open areas rather than break. In the related Mythbusters episode, it required liquid nitrogen (which is likely much colder than a 0-level spell), and it still needed an impact to break the lock.

  5. This is much more situational, but some doors (especially doors designed for security) don't open just because the locking mechanism is broken. If a door has a deadbolt attached to the lock, then breaking the lock won't let you open the door anyway. And if this trick works in a particular world, then it's very likely that locksmiths will adapt to this technique, and make locks that stay locked after being broken.

  • 7
    \$\begingroup\$ Liquid nitrogen / impact is a completely different physical effect (making the lock brittle, not forcing it apart). I very much agree with the difficulty of keeping the lock filled with water long enough, though. \$\endgroup\$
    – DevSolar
    Commented Jul 5, 2012 at 7:42

Generally speaking, instantaneous spells don't have any unintended side-effects. Just because a spell deals a certain type of damage doesn't mean that that spell has any effect related to the damage it's doing, besides the damage.

Pathfinder rules on catching fire state that a character must be "exposed to burning oil, bonfires, and non-instantaneous magic fires" (emphasis mine.)

This is why spells like Scorching Ray can never set something on fire. It simply deals fire damage. This is also why Burning Hands specifically states that "flammable materials burn if the flames touch them," and the reason for the spell Spark.

Freezing effects are slightly more ambiguous, since there's no line stating the effects of instantaneous magical cold. However, we can look at certain other cold spells, such as Freezing Sphere, which specifically states that it freezes water.

Given all this, the fact that the wording of Ray of Frost in no way implies any effect other than cold damage, and the mere fact that it's a zero-level spell, I would rule that as written, it does not freeze any water.

Of course, it's pretty cool, and if your DM is okay with it, go for it!

  • \$\begingroup\$ "it does not freeze any water." With the exception of Wall of Water, which explicitly states it freezes from anything that deals cold damage. \$\endgroup\$
    – Egor Hans
    Commented Nov 11, 2021 at 9:34

Putting aside the question of whether the water freezes, I'm skeptical that the addition of ice could open a lock. It would certainly block a key from being inserted. With enough expansion it might even mess up the internals enough to keep the key from working. But I just can't see it expanding in such a way that the lock opens. The lock is not an airtight system. It has a keyhole. Wouldn't freezing water simply be expelled from the keyhole?

As a GM you could probably convince me that you could temporarily jam a lock this way, but I don't see it opening. You'd have to fill a a Masterlock with water and leave it in the freeze for a combat or three as proof of concept.

(Now if you sealed the lock to make it airtight once water was inside, and heated it until the water became steam, that might open the lock enough to get inside it and open things up.)


One question here is whether a ray of frost is sufficient to freeze the water. And that depends entirely on how the GM interprets the spell.

Then there is whether the lock will actually break. I think that would depend on the lock type. Some might be robust (or simple) enough that they can take the pressure.

Then there is whether the lock breaks so that it can be opened, or whether it breaks so that it cannot be unlocked.

DM rulings all around.

  • \$\begingroup\$ Comments are not for extended discussion; this conversation has been moved to chat. \$\endgroup\$
    – mxyzplk
    Commented Dec 1, 2016 at 2:57

Assuming you could use some magical effect that quickly froze water, I myself was skeptical that freezing water could exert enough force to break an iron or steel lock, but a bit of googling reveals that freezing ice exerts somewhere between 1,000 and 2,000 atmospheres. This seems like an awesome amount of force, surely enough to break open a locking mechanism. However, as others noted, the problem is that this pressure flows to the path of least resistance, so the ice would expand out the keyhole, and whatever other cracks and holes were in the lock, without exerting much force on the lock itself. But even if you could sufficiently seal up the lock enough to totally contain the expanding ice, it might not actually break the lock. Freezing water expands about 9% when frozen, so it might only end up cracking the metal a bit, rather than bursting it open entirely.


Warlocks could just baleful utterance it at level one, but shatter and knock are both level 2 spells.

If it was like just a hobgoblin or kobold constructed cage, you know the kind of low level, iffy prisons a pc would be locked in, then you probably COULD freeze the water around the lock, then smash it with a morningstar or mace.

There'd be no reason not to just attack the enclosure itself however, unless it was made of steel or some such. Alternatively no reason why you couldn't just blast your way out with brute force, well maybe if the door caging you in was part of the foundation....

So no, no ray of frost + bucket of water would do the trick, even if you froze the water and got the lock inside (somehow) rather than just the keyhole ..... why have you gone through the extra effort when you could just brute force the door itself?

  • 1
    \$\begingroup\$ Welcome to rpg.se! Please take a look at the tour and the help; they're a useful introduction to the site. Could you spend a bit more text on why you think this strategy wouldn't work, please? Stack Exchange answers try to focus on the question at hand, and right now this answer dedicates more text to alternative ideas than it does to the actual question. And once you have 20+ rep, feel free to join the chat! \$\endgroup\$
    – BESW
    Commented Oct 2, 2013 at 6:52

I'm gonna be brief. The lock, water or not, still needs a certain amount of damage to be broken, hardness included. Maybe add some damage (they're using one more spell slot after all. Something like two rays of frost would be nice. They don't get to memorize a ra of frost but a more versatile spell, and that's their reward for being inventive.)

Second. Usually breaking the lock's gears means it's stuck now. FYI, even shooting into the keyhole does exactly this. Locks the door -more-.

In 4e, just deal damage as appropriate for the single spell. I know, that does not encourage creativity but it's a good thing believe me. You don't want smart players be able to convince you they can do everything without even using the rules, while not-so-smart ones never get anything from the game.


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