Today [the day I wrote the review and posted on LibraryThing], at the grocery store, I saw vitamin C tablets. My first impulse was to stock up and buy them all . . . which sums up the impact this book had on me this week. Near the end of the book, the local doctor explains that a lot of people had scurvy and the vitamin C was worth its weight in gold.
Overall, this disaster novel was powerful . . . I could not put it down and stayed up half of the night to finish it. Every few years, a disaster (particularly earth science-related) book gets my attention that pulls me in immediately. I look forward to the sequel.
I have to agree with another reviewer, in that I wish we had a chance to get to know the protagonist, Alex, a little more in the time before the disaster (the huge dormant volcano under Yellowstone blows, and Iowa is in the "red zone"). We get hints as to his previous life, but they are brief and fleeting. What we know most is that he is good at tae kwan do, because that comes in handy in his travels to reconnect with his family.