Race For Existence- YA sci-fi

Bryer's life is all about lattes and online schooling in a completely electric society of the future. But when a solar flare sends a storm our way, it results in an EMP strike around the globe. All power is lost. Bryer must journey from Washington D.C. to Cape Canaveral on foot, and she'd better hurry. Her father is one of the last astronauts that will be arriving as the fifth settlement to Mars, and if she misses that flight, she'll have no one in the world for a family. 

Bryer battles every step of the way, death a constant threat. And the people she meets along the way range from helpful to crazy. She even finds a small city in a Walmart on the way. She felt the weight of being responsible for three people, and she wouldn't have believed she could do it. But could she? Getting sick was never in the plan...