Environment Hazards

The SRD defines several environmental dangers characters may face during exploration.

At the end of a fall, a creature takes 1d6 bludgeoning damage for every 10 feet it fell, to a maximum of 20d6 (200 feet). The creature lands prone unless it avoids taking damage from the fall.

A creature can hold its breath for 1 + CON modifier minutes (minimum 30 seconds). When out of breath, it can survive for CON modifier rounds (minimum 1). At the start of its next turn after that, it drops to 0 HP and is dying.

• Bright light — normal vision for all creatures
• Dim light — creates a lightly obscured area; Perception checks relying on sight have disadvantage
• Darkness — creates a heavily obscured area; creatures effectively suffer the blinded condition
• Darkvision — see in dim light as bright light, darkness as dim light (no color, only grayscale)
• Blindsight/Tremorsense/Truesight — sense without relying on normal sight

Every foot of movement in difficult terrain costs 1 extra foot. Difficult terrain includes dense forests, rubble, steep stairs, snow, shallow bogs, and similar obstacles.

• Extreme cold (0°F / -18°C or below): DC 10 CON save each hour or gain 1 level of exhaustion. Creatures with cold resistance or immunity auto-succeed, as do those in cold weather gear.
• Extreme heat (100°F / 38°C or above): DC 5 CON save each hour (+1 per subsequent hour) or gain 1 level of exhaustion. Heavy armor imposes disadvantage.

Exhaustion has 6 levels. Each level imposes cumulative penalties. Level 6 results in death.