After the Snow — S.D. Crockett

The oceans stopped working before Willo was born, so the world of ice and snow is all he's ever known. He lives with his family deep in the wilderness, far from the government's controlling grasp. Willo's survival skills are put to the test when he arrives home one day to find his family gone. It could be the government; it could be scavengers--all Willo knows is he has to find refuge and his family. It is a journey that will take him into the city he's always avoided, with a girl who needs his help more than he knows.