Incendiary Runes

You trace mystic runes upon a target point. The runes immediately detonate, causing a small surge of flames and dealing 1d6 points of fire damage to every creature within 10 feet. Those creatures catch fire unless they succeed at Reflex saves. A burning creature takes 1d6 fire damage each round for 1 minute. Each round, it attempts a Reflex save to end the burning.