Environment (Rules) (865-environment)

Primarily used during exploration, environment rules bring the locales your party travels through to life. You'll often be able to use common sense to adjudicate how environments work, but you'll need special rules for environments that really stand out. Each of the environments presented in this section uses the terrain rules in different ways, so be sure to familiarize yourself with those rules before reading this section. Some environments refer to the rules for climate and natural disasters. Many places have the traits of multiple environments; a snowcovered mountain might use both the arctic and mountain environments, for example. For environmental features with effects based on how tall or deep they are, those effects vary further based on a creature's size. For instance, a shallow bog for a Medium creature might be a deep bog for smaller creatures, and a deep bog for a Medium creature could be only a shallow bog for a larger creature (and so insignificant for a truly massive creature that it isn't even difficult terrain). The Environmental Features table (see below) lists the features of various environments alphabetically for quick reference. The Proficiency DC Band entry indicates a range of appropriate simple DCs for that environmental feature while also providing a rough estimate of the danger or complexity of the feature. ### Environmental Features Feature Proficiency DC Band Airlocks Untrained–trained Atmosphere — Avalanches Expert–legendary Blizzards — Bogs Untrained–trained Catwalks Untrained-trained Canopies Trained–master Chasms — Collapses Expert–legendary Cosmic Radiation Expert–legendary Crowd Trained–master Currents Trained–master Decompression Untrained–expert Doors — Earthquakes Trained–legendary Elevators — Floods Expert–legendary Floors Untrained–expert Fog — Gravity — Gravity Wells Trained–master Ice Trained–master Lava Expert–legendary Magnetic Storm Trained–master Maintenance Tunnels Untrained–expert Precipitation — Psystorms Expert–legendary Radiation — Rooftops Trained–master Rubble Untrained–expert Sand Untrained–expert Sandstorms Trained–master Security — Sewers — Slopes Untrained–trained Snow Untrained–expert Stairs Untrained–trained Streets Untrained–trained Temperature — Tornadoes Master–legendary Trees Untrained–master Tsunamis Master–legendary Underwater Visibility — Vacuum Untrained–trained Volcanic Eruptions Trained–legendary Vortex Expert–legendary Walls See entry Wildfires Expert–legendary Wind Untrained–legendary Terrain Rules Environments make frequent use of the rules for difficult terrain, greater difficult terrain, and hazardous terrain, so those rules are summarized here. Difficult terrain is any terrain that impedes movement, ranging from particularly rough or unstable surfaces to thick ground cover and countless other impediments. Moving into a square of difficult terrain (or moving 5 feet into or within an area of difficult terrain, if you're not using a grid) costs an extra 5 feet of movement. Moving into a square of greater difficult terrain instead costs 10 additional feet of movement. This additional cost isn't increased when moving diagonally. Creatures can't normally Step into difficult terrain. Any movement creatures make while jumping ignores terrain that the creature is jumping over. Some abilities (such as flight or being incorporeal) allow creatures to avoid the movement reduction from some types of difficult terrain. Certain other abilities let creatures ignore difficult terrain while traveling on foot; such an ability also allows a creature to move through greater difficult terrain using the movement cost for difficult terrain, but unless the ability specifies otherwise, these abilities don't let creatures ignore greater difficult terrain. Hazardous terrain damages creatures whenever they move through it. For instance, an acid pool, a corridor filled with molten slag, and a field of razor-sharp grass all constitute hazardous terrain. The amount and type of damage depend on the specific hazardous terrain.