On April 3, 1974, all hell broke loose in the central United States and southern Ontario. In the next 40 hours of the "Super Outbreak," 148 record-breaking tornadoes tore through 13 states, from Michigan to Alabama. The twisters killed more than 300 people and left over 5,000 others injured. F5 recounts the nearly unbelievable destruction wrought by a "perfect storm" system that experts calculate could occur only once every 500 years. A truly riveting read.