The Environment

A fall from a great height is one of the most common hazards facing an adventurer. At the end of a fall, a creature takes 1D6 Bludgeoning damage for every 10 feet it fell, to a maximum of 20D6. The creature lands Prone, unless it avoids taking damage from the fall.

A creature can hold its breath for a number of minutes equal to 1 + its CON modifier (Minimum of 30 seconds). When a creature runs out of breath or is choking, it can survive for a number of rounds equal to its CON modifier (Minimum 1). At the start of its next turn, it drops to 0 hit points and is dying, and it can’t regain hit points or be stabilized until it can breathe again.

For example, a creature with a CON of 14 can hold its breath for 3 minutes. If it starts suffocating, it has 2 rounds to reach air before it drops to 0 hit points.

The most fundamental tasks of adventuring— noticing danger, finding hidden objects, hitting an enemy in combat, and targeting a spell, to name just a few—rely heavily on a character’s ability to see. Darkness and other effects that obscure vision can prove a significant hindrance.A given area might be Lightly or Heavily Obscured.

• Lightly Obscured: In a Lightly Obscured area, such as Dim Light, patchy fog, or moderate foliage, creatures have disadvantage on Perception checks that rely on sight.

• Heavily Obscured: A Heavily Obscured area—such as Darkness, opaque fog, or dense foliage—blocks vision entirely. A creature effectively suffers from the Blinded condition when trying to see something in that area.

The presence or absence of light in an environment creates three categories of illumination: bright light, dim light, and darkness.

Bright Light lets most creatures see normally. Even gloomy days provide Bright Light, as do torches, lanterns, fires, and other sources of illumination within a specific radius.

Dim Light, also called shadows, creates a Lightly Obscured area. An area of Dim Light is usually a boundary between a source of Bright Light, such as a torch, and surrounding Darkness. The soft light of twilight and dawn also counts as Dim Light. A particularly brilliant full moon might bathe the land in Dim Light.

Darkness creates a Heavily Obscured area. Characters face darkness outdoors at night (even most moonlit nights), within the confines of an unlit dungeon or a subterranean vault, or in an area of Magical Darkness.

Sunlight provides Bright Light but also is different in that it has an almost magical effect on certain creatures and is rarely reproducible with spells or other similar effects.

A creature with Blindsight can perceive its surroundings without relying on sight, within a specific radius. Creatures without eyes, such as Oozes, and creatures with echolocation or heightened senses, such as bats and true dragons, have this sense.

Many creatures in fantasy gaming worlds, especially those that dwell underground, have Darkvision. Within a specified range, a creature with Darkvision can see in Darkness as if the Darkness were Dim Light, so areas of Darkness are only Lightly Obscured as far as that creature is concerned. However, the creature can’t discern color in Darkness, only shades of gray.

A creature with Truesight can, out to a specific range, see in normal and magical Darkness, see Invisible creatures and objects, automatically detect visual illusions and succeed on saving throws against them, and perceive the original form of a shapechanger or a creature that is transformed by magic. Furthermore, the creature can see into the Ethereal Plane.

A creature with Tremorsense can, out to a specific range, detect creatures and phenomenon by detecting vibrations. This can detect unseen creatures that are living as all living creatures have internal noise. This cannot be used to detect motionless or levitating or flying objects. Certain surfaces such as fast water and soft sand may shorten the range while hard surfaces such as packed earth and metal may extend the range.

Swimming through deep water (more than 100 feet deep) presents additional challenges because of the water’s pressure and cold temperature. After each hour of swimming in deep water, a creature that lacks a Swim Speed must succeed on a DC 10 CON saving throw or gain 1 Exhaustion level.

A creature can be immersed in frigid water for a number of minutes equal to its Constitution score before suffering any ill effects. Each additional minute spent in frigid water requires the creature to succeed on a DC 10 Constitution saving throw or gain 1 Exhaustion level. Creatures with Resistance or Immunity to Cold damage automatically succeed on the save, as do creatures that are naturally adapted to living in ice-cold water.

When the temperature is 0 degrees Fahrenheit or lower, a creature exposed to the extreme cold must succeed on a DC 10 Constitution saving throw at the end of each hour or gain 1 Exhaustion level. Creatures that have Resistance or Immunity to Cold damage automatically succeed on the save.

When the temperature is 100 degrees Fahrenheit or higher, a creature exposed to the extreme heat and without access to drinkable water must succeed on a Constitution saving throw at the end of each hour or gain 1 Exhaustion level. The DC is 5 for the first hour and increases by 1 for each additional hour. Creatures wearing Medium or Heavy armor have Disadvantage on the save. Creatures that have Resistance or Immunity to Fire damage automatically succeed on the save.

Everything within an area of heavy rain or heavy snowfall is Lightly Obscured, and creatures in the area have Disadvantage on all Wisdom (Perception) checks. Heavy rain also extinguishes open flames.

Traveling at altitudes of 10,000 feet or higher above sea level is taxing for most creatures because of the reduced amount of oxygen in the air. Each hour such a creature spends traveling at high altitude counts as 2 hours for the purpose of determining how long that creature can travel (see “Travel Pace”).

Creatures can become acclimated to a high altitude by spending 30 days or more at this elevation. Creatures can’t become acclimated to elevations above 20,000 feet unless they are native to such environments.

Slippery ice is Difficult Terrain. A creature that moves onto slippery ice for the first time on a turn or starts its turn there must succeed on a DC 10 Dexterity saving throw or have the Prone condition.

Strong wind imposes Disadvantage on ranged attack rolls with weapons. It also extinguishes open flames and disperses fog. A flying creature in a strong wind must land at the end of its turn or fall.

A strong wind in a desert can create a sandstorm that imposes Disadvantage on Wisdom (Perception) checks.

Thin ice has a weight tolerance of 3d10 × 10 pounds per 10-foot-square area. Whenever the total weight on an area of thin ice exceeds its tolerance, the ice in that area breaks. All creatures on broken ice fall through. Below the ice is frigid water.