Abusing Cloudkill

[Jhyrryl]

What happens when cloudkill hits a barrier? Does it change direction or stop? Does the angle of the barrier matter?

 

[Norfleet]

What happens when cloudkill hits a barrier? Does it change direction or stop? Does the angle of the barrier matter?

When a cloudkill hits a barrier, assuming the barrier is impermeable, such as a wall of force, it stops, obviously unable to travel anywhere, being a gaseous cloud and all. Eventually, it will come to a hemispherical clump against the wall.

As for non-perpendicular barriers, that's an application of physics. You have a 20 foot high heavier than air "cloud". It trundles along at 10 feet per round, a round being 6 seconds, which gives us a speed of 1.67 ft/s. Gravity is 32 ft/s^2. Gravity will overcome any part of the cloud attempting to "climb" at its 1.67 ft/s rate in less than a second. This means that any barrier the cloud runs into that is in excess of 20 feet in height will basically stop cold, and a barrier of less than that will result in the top of the cloud piling over it, moving over the barrier, and then dropping to the ground on the other side, presumably hauling the rest of the cloud with it by magic. The cloud then piles up against the barrier. What form it takes upon piling up against the cloud is open to interpretation, depending on whether you wish to consider the fact that the cloud is obviously forced to retain a certain density and mass by magic, or else it would disperse radially in the absence of wind, rather than travelling as a cohensive cylindrical burst, or whether it's forced to maintain its cylindrical shape, and the parts which intersect with solid objects are simply truncated.

 

[shilsen]

Prithee, what be this phee-zicks thou prattlest about?

 

[Magic Slim]

lol (I'm not laughing at the post. It was a well thought out and logical post)

As for non-perpendicular barriers, that's an application of physics. You have a 20 foot high heavier than air "cloud". It trundles along at 10 feet per round, a round being 6 seconds, which gives us a speed of 1.67 ft/s. Gravity is 32 ft/s^2. [...]presumably hauling the rest of the cloud with it by magic. [...]

I love this forum

Slim

 

[Norfleet]

Clouds striking barriers which are not horizontally perpendicular to the direction of travel poses another interesting question. If the cloud is assumed to collide inelastically, and unable to cross the barrier as above, then the cloud will be deflected along the barrier and travel along the barrier at speed equal to 10cos(theta) ft/r, or 1.67cos(theta) ft/s, where theta is the smaller of the angles between the cloud's direction of travel, and the barrier, in radians. If your angle is in degrees, multiply by Pi/180 to get the angle in radians.

Cloudkills that run into long curving barriers are messy, since evaluating the cloudkill's velocity will now require calculus, which I'm not paid enough to get into.

Alternatively, if all of this math is too bothersome, make an arbitrary ruling by fiat. It's not as if the behavior of magical clouds is a well-documented phenomenon anyway.

 

[Magic Missile]

Nicely done. Who says you can't use physics to describe magic?

Next question: how many Shocking Grasp spells would it take to provide the required voltage to work a hairdryer?

 

[Jhyrryl]

Heh. Thanks for the opinions.

 

[Centaur]

Nicely done. Who says you can't use physics to describe magic?

Next question: how many Shocking Grasp spells would it take to provide the required voltage to work a hairdryer?

Actualy the voltage delivered by a shocking grasp spell is likely much higher than that needed to run a hair dryer. The typical voltage of a static shock when you can hear it is often around 5000V and to see it at normal room illumination is typicaly around 10,000V.

The real question that you should be asking is total power delivery. How many Watts of electrical energy is delivered by a single shocking grasp spell. Or maybee it could be broken down by the points of damage.

Actualy, to be perfectly accurate, Watts is a rating of energy over unit time, to what we realy need to do is find out how many Joules of energy a Shocking grasp delivers and then divide that by the time it takes to deliver (1 action). For argument purposes lets use 6 seconds (one round) ...... is anyone listening...?

 

[Jhyrryl]

More Questions

I got myself thinking...dangerous business, I know.

Would a cloudkill that hits the end of a wall of force split and move on both sides?

If so, what if the wall was at an angle to the direction of the cloud's direction of travel, would the cloud form two pieces that are now travelling in different directions?

If not, would it shift entirely to one side of the wall or the other, so as to take up the same space as before? Or would it get stuck?

What if a wall of force is cast into an area containing a cloudkill?

 

[Norfleet]

Any of the above cases would create a massive disruption in the space-time continuum that would completely consume the universe within 1d4+1 rounds.