Mullin's Ashfall is a page turner. If you have ever been to Yellowstone, you will want to read this book. If you have ever taken Karate lessons, you will want to read this book! Alex begins a journey to find his family, he meets up with a survivor, Darla and their comradery sets the pace for this story. Volcano ash sets the tone of the story, much like C. McCarthy's The road, a tale of survival and social regression.
Check out the information on Yellowstone at: http://volcanoes.usgs.gov/observatories/yvo/index.html