Ashes trilogy (Ilsa J. Bick)

An electromagnetic pulse flashes across the sky, destroying every electronic device, wiping out every computerized system, and killing billions. When it happens, Alex was hiking in the woods to say good-bye to her dead parents and her personal demons. Now desperate to find out what happened after the pulse crushes her to the ground, Alex meets up with Tom—a young soldier—and Ellie, a girl whose grandfather was killed by the EMP. For this improvised...

"Alex and Tom's future is uncertain as they continue the struggle to survive in a post-apocalyptic world, and their lives are threatened by the Changed and other human survivors"