Black Snow Days — Claudia O'Keefe

Eric Pope crashed into a wall ...
Twelve years later, he wakes from a coma to find the world destroyed by war -- and his body and mind rebuilt into something more and less than human. Eric is now the only man who can survive in the deadly black snow outside the Tank. The half-mad survivors of the war see him as their promised savior. And what's been done to his mind is even more alarming: another personality lives within him, an independent intelligence that is his own female self ...