Ashes by Ilsa J. Bick

Alex is on a final hike before a brain tumor devours her last days of life when an electromagnetic pulse wipes out every computerized system, kills most adults, and changes nearly all teenagers into cannibalistic zombies. The strange pulse leaves a select few, including a now possibly tumor-free Alex, with heightened senses. Initially lost and alone in her new world, Alex meets a soldier named Tom and an orphaned girl. The first half of the novel follows this makeshift family as they fight to survive in the wilderness and avoid crazed zombies, while the second half follows Alex’s discovery of other camps of survivors and the subcultures birthed by the zombie apocalypse. Set almost entirely in a never-ending expanse of desolate woods, Bick’s first of her zombie trilogy is a brutal, grim, and tense novel about survival in a world with horrors lurking in every shadow.