A fireball spell is a burst of flame that detonates with a low roar and deals 1d6 points of fire damage per caster level (maximum 10d6) to all creatures within the area. Unattended objects also take this damage. The explosion creates almost no pressure.

The character points a finger and determine the range (distance and height) at which the fireball is to burst. A glowing, pea-sized bead streaks from the pointing digit and, unless it impacts upon a material body or solid barrier prior to attaining the prescribed range, blossoms into the fireball at that point (an early impact results in an early detonation). If the character attempts to send the bead through a narrow passage, such as through an arrow slit, the character must "hit" the opening with a ranged touch attack, or else the bead strikes the barrier and detonates prematurely.

The fireball sets fire to combustibles and damages objects in the area. It can melt metals with a low melting point, such as lead, gold, copper, silver, or bronze. If the damage caused to an interposing barrier shatters or breaks through it, the fireball may continue beyond the barrier if the area permits; otherwise it stops at the barrier just as any other spell effect does.