Erupting Firebolt (3.5e Spell)

You fire a bolt of bright flame which fly off and explode, sending a cone of ash and flame all over your enemies.

Upon finishing casting this spell you fire a 60-ft. line, at any point during this line you may have it stop and explode into a 20 feet cone-shaped spread pointing at the same direction of the line. Any creatures caught within the spell area take 1d6 fire damages per caster level (maximum of 10d6), creatures caught by both the line and cone take an extra 2d6 fire damage.

This spell leave ash residue on the ground, the area that the cone occupies is difficult terrain. Light wind will disperse the ashes over the course of 10 minutes, moderate wind over the course of 1 minute while severed or stronger wind will disperse it in 1 round.