Alright, let me put all of us out of our misery and say simply: not my thing. 
 First off, though I can tolerate (is secretly writing a) dystopian, apocalyptic doom-and-gloom "we're all gonna die!" novels are not up my alley. I know exactly how many ways humanity can be wiped out within the time frame of a day, thank you very much. I don't need it to be thrust in my face in grotesque detail every single day. 
 Ostrich-like mentality? I don't think so. I prefer to stay cheerful and optimistic rather than waiting for my roof to fall in on my head. 
 Ashfall centers around the (extremely slim) possibility of the supervolcano currently slumbering in Yellowstone exploding and ending life in the U.S. as we know it. Think Pompeii on a freakishly huge, inescapable level. And of course, a lack of food and hope brings out the worse in people. 
 And the author makes sure we know this in gruesome, graphic detail. 
 There is rape. There is cannibalism. There are underage teenage relations (which feel to me as though they take up the majority of the "conflict" of the last few chapters, as compared to more important urgent issues like food or surviving the next twenty-four hours). There is homosexuality. Simply put, if you're the type of person who takes offense at any/all of that, this book is going to have you running in the opposite direction like a bat out of Hell. 
 My suggestion? Leave it and keep going.