Impact Hour - Impact Hour, #1

Nobody saw the asteroid coming until too late. Tessa Karsten and her younger brother have spent the past three years homeless, on the run from a deadly past, and hunted by those who should be their family. Now, at the University of Alabama, Tessa can finally rebuild her shattered life. The asteroid strikes far away, but those who died on impact were the lucky ones. Now she's trapped on campus as fire rains from the sky and countless die.
Teaming up with Alex, a university student with a tragic past, could be her best chance of survival and of reaching her brother. Together, they must lead their band of survivors to safety. Time is running out for her brother at home, and the past creeps closer all the time. Soon, it will catch up. Her dark past, it turns out, is closer than she thinks.