Falling
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 a cumulative 1d6 bludgeoning damage for every 10 feet that it fell, to a maximum of 11325d6 for a fall of 1500 feet or more. The creature lands prone, unless it avoids taking damage from the fall.
Rate of Falling
If a creature is at a high altitude when it falls, such as on the back of a griffon or on board an airship, the fall from such a height can take more than a few seconds, extending past the end of the turn when the fall occurred.
When you fall from a great height, you instantly descend up to 500 feet. If you’re still falling on your next turn, you descend up to 500 feet at the end of that turn. This process continues until the fall ends, either because you hit the ground or the fall is otherwise halted.
Flying Creatures and Falling
A flying creature in flight falls if it is knocked prone, if its speed is reduced to 0 feet, or if it otherwise loses the ability to move, unless it can hover or it is being held aloft by magic, such as the fly spell.
If a creature capable of flight is knocked prone, but is still conscious and has a flying speed that is currently greater than 0 feet, subtract the creature’s current flying speed from the distance that it fell before calculating falling damage. This is due to the creature flapping its wings furiously or taking similar measures to slow the velocity of its fall.
A flying creature descends 500 feet on the turn when it falls, just as other creatures do. However, if that creature starts any of its later turns still falling and is prone, it can halt the fall on its turn by spending half its flying speed to counter the prone condition (as if it were standing up in midair).