Ark: Diaspora

Four years had passed since a massive asteroid collided with Earth and triggered an environmental disaster that obliterated nearly all forms of life. Monumental tsunamis demolished coastal cities globally, and volcanic eruptions throughout the world belched out a veil of ash that deflected sunlight and caused a new ice age in which billions of people perished. In this forbidding world under an orange-tinged sky, small groups of humans managed to survive, as the first book in this trilogy, Ark: Asteroid Impact, describes. 

Amid crushed buildings buried in snow on the beaches of California, survivors pieced together the means to begin exploring the wounded world to see who else may remain. They courageously rescued other isolated refugees who were facing starvation. As they communicated by radio, a Russian missile installation intercepted the transmissions. The Russians saw an opportunity to use thermonuclear weapons to assert world domination.