Faerie Fire vs. Fog

[Jeff the Green]

My players are fighting a group of zombies in the fog, and to reduce miss chances the drow used her faerie fire SLA. The text is
A pale glow surrounds and outlines the subjects. Outlined subjects shed light as candles. Outlined creatures do not benefit from the concealment normally provided by darkness (though a 2nd-level or higher magical darkness effect functions normally), blur, displacement, invisibility, or similar effects. The light is too dim to have any special effect on undead or dark-dwelling creatures vulnerable to light. The faerie fire can be blue, green, or violet, according to your choice at the time of casting. The faerie fire does not cause any harm to the objects or creatures thus outlined.
Should it work to remove the concealment of the fog?

[AntiTrust]

Yeah it would, it affects magical darkness and many other powerful effects like invisibility and displacement. It seems very much the intent that mundane effects of concealment such as fog rolling in from the hills would also be negated for those effected by the spell. The spell does have SR so if you really want them to fight with the penalty of concealment you'll need to throw out some critters that have SR or some other ability. I personally like water elementals' ability to "drench" even magical light with an opposed caster level check.

[Curmudgeon]

If it's a magical fog effect then yes, otherwise no. Natural fog isn't an "effect"; it's an environmental moisture condition along with rain, sleet, and snow.

[Crasical]

The spell makes things get a glowing outline. Would a thing with a glowing outline be easier to see in a fog bank than something without a glowing outline? I'm going to go ahead and say yes, it would be. So yes, Fairy Fire would negate the miss chance caused by fog.

[ericgrau]

If it were a high intensity light then it could pierce fog. But the spell description says it's as bright as candlelight so I'm gonna say no. I suppose it could negate the 5 foot partial concealment (20%) but beyond that you might as well be asking "Can faerie fire be seen on the other side of a magical wall, that's concealment right?" Uh, nah.

Every single example listed provides concealment without masking the subject, so in those cases a faintly glowing outline actually makes sense. But once you block that outline, I don't think so. And there are about 17 different fog effects in the player's handbook so it would seem odd that they didn't put in at least one example like they did for invisibility. Every single type of concealment spell in the srd is listed except the fogs, tiny hut and blink. Tiny hut likewise creates a visual barrier and blink shunts both them and the light onto another plane.

[Darrin]

Should it work to remove the concealment of the fog?

Yes, this works to cancel the miss chance from concealment, so long as your target is within 5' (or on the edge of the cloud). But faerie fire stops working if there's more than 5' of fog between you and your target. From weather effects in the SRD:

"fog obscures all sight, including darkvision, beyond 5 feet."

If you're trying to fire ranged weapons into the fog, you need some way to pinpoint which square your target is in: blindsense, tremorsense, mindsight, and really good Listen checks let you pinpoint, but the target still gets a 50% miss chance due to total concealment. Blindsight is much better: not only does it pinpoint, there is no miss chance.

[Jeff the Green]

Darrin, I think you're reading that sentence out of context. The entire paragraph reads:

Whether in the form of a low-lying cloud or a mist rising from the ground, fog obscures all sight, including darkvision, beyond 5 feet. Creatures 5 feet away have concealment (attacks by or against them have a 20% miss chance).
In this instance, I don't think obscured means blocked.

I'm convinced by RAW Curmudgeon is right (again), but for simplicity's sake I'm going to say it works.

[Keld Denar]

If it's a magical fog effect then yes, otherwise no. Natural fog isn't an "effect"; it's an environmental moisture condition along with rain, sleet, and snow.

Non-magical darkness is not an "effect" either, yet it is included in the list. Ruling out non-magical fog because it is not an effect while including non-magical darkness because it is explicitly included seems overly pedantic and non-nonsensical. If non-magical darkness is included, non-magical fog should be as well, as long as the hitter and the hitee are within 5' of each other (since total concealment would block the effect) since they are "similar" as indicated in the text. This list is inclusive, not exclusive.

Non-magical darkness may not be an effect in the spell sense, but it still affects a character in a way that is considered an effect. The word "effect" is not purely the realm of spells and abilities.

[Curmudgeon]

I'm convinced by RAW Curmudgeon is right (again), but for simplicity's sake I'm going to say it works.
I think the old adage "Trust, but verify" is good advice here.

Non-magical darkness is not an "effect" either, yet it is included in the list. Ruling out non-magical fog because it is not an effect while including non-magical darkness because it is explicitly included seems overly pedantic and non-nonsensical.
You're quite right, and it's my fault for not looking up the spell again. I had misremembered "provided by darkness" as "provided by darkness"; the fact that the vBulletin quote function puts everything in italics made Jeff the Green's SRD quote ambiguous, and my memory was faulty.

ericgrau has thought this one through better than I. The light of each Faerie Fire will function in normal fog just as well as a candle would, overcoming concealment within the 5' radius of shadowy illumination.

I apologize for my error.

[Invader]

I'd say that it doesn't work.

Candle light is sufficient to penetrate darkness but it's not sufficient to penetrate fog so I don't think it'd offer a bonus. At the most it might give you an extra 5 feet of visibility.

[Deophaun]

First, this is definitely DM adjudication territory. So, my advice is to go with what's fun for the party.

That said, as I read it, no, it has no effect on fog, as fog is not similar to any of the other effects listed. If we're going with magic spells, you have an evocation and a bunch of illusions. Fog cloud, obscuring mist, and other like spells are conjurations. They work by placing something in between the viewer and the target, which none of the other effects do. Same deal with a naturally occurring fog bank.