Enivronmental Hazards: CR & XP

[Meth In a Mine]

Hello all,

Just as the title says, I want to know how environmental hazards influence Challenge Ratings and XP gains of encounters. To give context, I'm writing an adventure that's set in an extremely cold climate. To make things harder and more thematic, they'll be dealing with environment hazards throughout. For example, they'll have to fight saber-tooth tigers in a whiteout blizzard, a giant ice toads trying to pull them into glacial crevasses, or just having to deal with Blood Snow, Death Hail, and the like for prolonged periods of time.

For those of you wondering, yes, I'm having a lot of fun with Frostburn. I'm also writing an adventure set in a completely different locale since I know at least one member of my group frequents these forums so I'm don't want them to get too cozy.

So in summary, how do I adjust CRs and XP rewards? Most of these hazards are only a problem for the PCs, so it WILL be harder than if the PCs faced these monsters during normal conditions.

Thanks in advance,
-MiaM

[Klara Meison]

There are two ways to do that that I know of. First is to count those hazards as traps, and count XP accordingly. Look up how traps function in your system of choice, there are probably books on how to deal with trap XP. Second way is to use heuristic methods, and adjust encounter cr by +-1 depending on wherever environment will be seriously disadvantageous/advantageous to the PCs. Obviously that requires some experience and experimentation, but encounter building is 30% science, 70% art anyways.

[MesiDoomstalker]

There are two ways to do that that I know of. First is to count those hazards as traps, and count XP accordingly. Look up how traps function in your system of choice, there are probably books on how to deal with trap XP. Second way is to use heuristic methods, and adjust encounter cr by +-1 depending on wherever environment will be seriously disadvantageous/advantageous to the PCs. Obviously that requires some experience and experimentation, but encounter building is 30% science, 70% art anyways.

The rule of thumb is if the environment favors the NPC, it should be +1 CR, +2 if it heavily stacked against the PCs. Same goes for the opposite.

[Klara Meison]

The rule of thumb is if the environment favors the NPC, it should be +1 CR, +2 if it heavily stacked against the PCs. Same goes for the opposite.

Everyone has different thumbs.

[NerdHut]

It should be considered that CR assumes the environment to an extent, particularly if the monster manual (or other book) mentions a specific location. An Earth Elemental in a cave or stoney dungeon would be at normal CR. But a shark on land is basically a 1/3 CR, because it's so far from its natural surroundings.

With that in mind, if your players are fighting a Dire Polar Bear, I think it would be completely reasonable to place that battle in a mild snowstorm with difficult terrain like deep snow and still have the encounter be CR 11. But if you make it a blizzard and put it on patchy icesheet, then I would suggest upping the CR by 1 or 2.

For reference, the Tyrannosaurus has some fairly similar stats to the Dire Polar Bear. Everything is pretty close, except the bear's strength is higher. But the T-Rex is a CR 8, and the bear is a CR 11. In my mind, the Strength and different special abilities aren't enough to warrant a +3 to CR. Environment plays a part in that.

Basically, if the surroundings are appropriate, but not extreme (relative to the monster) then I think the CR should be about where it says in the book



This of course goes out the window if your players are completely unoptimized for the situation, such as land-based Azers trying to fight a Squid, in which case they'd be completely screwed. But that doesn't seem to be the case here.