Falling 

Falling more than 10ft (2 hexes) causes a character to take damage.
At 15ft (3 hexes), characters take 1 point of HP damage.
At 20ft (4 hexes), a character takes 1d6 damage, and an additonal 1d6 points of damage for every 10ft above 20.

Fall damage can be avoided by using the Tumble Skill