SRD:Rain of Fire

This spell summons a swirling thunderstorm that rains fire rather than raindrops down on the character and everything within a two-mile radius of him or her. Everything caught unprotected or unsheltered in the flaming deluge takes 1 point of fire damage each round. A successful Reflex save results in no damage, but the save must be repeated each round. Unless the ground is exceedingly damp, all vegetation is eventually blackened and destroyed, leaving behind a barren wasteland similar to the aftermath of a grass or forest fire. The fiery storm is stationary and persists even if the caster leaves.