I'm the author of the ASHFALL three-and-a-half-ology: ASHFALL, ASHEN WINTER, SUNRISE, and DARLA'S STORY.
I checked this book out from my library after someone at one of my author talks raved about it. I enjoyed it so much that I bought my own copy today--I'm certain that I'll reread it. It contains one of the best passages demonstrating the use of description of setting to convey emotion--what MFA'ers call the objective correlative--that I've yet read. I'm sure I'll wind up using this book when I teach writing workshops along with Winter's Bone by Woodrell.
This would be a great next read for those who loved Hatchet by Paulsen--a little more challenging, but full of similar survival-related themes. (And my own book, ASHFALL, could be a good next read for those who loved Touching Spirit Bear.) Highly recommended.