I had a player using spider climb in a small cave system, however the room flooded (quickly, with a high water pressure). Would he be able to hold on since he's using spider climb?
Alternatively, I thought of the same situation: while a person is normally scaling (climbing) a cliff wall, and water rushes down, should he just get a climb DC increase? (by how much?) or would he use a different skill, (I'd used a str check when the person is using a rope, and water rushes down.)
If the climb example would involve a DC increase, would that mean the spider climbing char does not need to roll:
furthermore, it need not make Climb checks to traverse a vertical or horizontal surface
Would indicate that the climb would not need to roll, except I saw this question "Alternative uses of Spider Climb" Which seemed to indicate that part is just a badly worded version of:
A creature with a climb speed has a +8 racial bonus on all Climb checks. The creature must make a Climb check to climb any wall or slope with a DC higher than 0, but it always can choose to take 10, even if rushed or threatened while climbing. If a creature with a climb speed chooses an accelerated climb (see above), it moves at double its climb speed (or at its land speed, whichever is slower) and makes a single Climb check at a -5 penalty. Such a creature retains its Dexterity bonus to Armor Class (if any) while climbing, and opponents get no special bonus to their attacks against it. It cannot, however, use the run action while climbing.
Thus the spider climb spell was a simplified version of having a climb speed (so you could climb any walls without caring about your climb score (otherwise you'd need points in climb, as you could just take 10 + 8 racial bonus))
Note: While I am looking for RAW, I don't expect this case to be covered. Thus house-rules, or RAI "fixups" are fine too.
Best Answer
Anaruoch: The Empire of Shade includes a 50-ft.-tall, 10-ft.-wide waterfall inside a cavern. Features of the Area describes the waterfall as follows:
Extrapolating from this, a creature that wants not to be swept away when confronted with a suddenly flooding passageway should probably allowed to make a Strength check (DC 20) if the creature has means of going against the deluge in the first place (e.g. appropriate handholds, a fly speed, an active effect like the spell spider climb, extreme weight due to the spell iron body). That is, effectively the creature has chosen to try to stay in place while the waterfall flows over the creature. Success means the creature can take its actions normally; I suggest failure means the creature's swept away (rather than having the creature plummet).
Success!
After a successful Strength check made to avoid being swept away, forward progress against this ersatz waterfall should require a climbing creature to make Climb skill checks (DC 35). (Note: While neither hydrologist nor spider-eating spelunker, I think that DC's about right considering the potential water speeds were discussing. I don't know if matters if failure means you technically fall or, instead, are technically swept away as both involve facing tons of water coming right at you! I'm guessing, but at this point traversing the horizontal seems like it should be as difficult as traversing the vertical. Comments can take up this issue, and, of course, the DM can adjust the DC as he sees fit.)
How other creatures make forward progress is up to the DM, but flying creatures likely must swim (perhaps in stormy waters), and super heavy creatures likely use their land speed (albeit maybe vastly reduced—this is, after all, pretty difficult terrain). All such creatures probably also need to hold their breath.
Failure!
After a failed Strength check, the creature's swept away. Aquatic Terrain under Flowing Water describes being swept away as follows:
Emphasis mine, and which should cover equally well a rapidly flooding cavern.