Out of the Blue — Jeffrey Thomas

No one understood the cause of the strange blue blizzard of ash. They were too busy trying to survive, as their towns were buried under it. Too busy trying to survive, when the ash coated the bodies of those it came in contact with...changing them horribly. Changing them into creatures with a hunger for human flesh...

OUT OF THE BLUE is a story of the end of the world, and the start of a new one, by Jeffrey Thomas -- author of the Punktown series, and the novels LETTERS FROM HADES and A NIGHTMARE ON ELM STREET: THE DREAM DEALERS.