For decades, the Seattle Sounders and the Portland Timbers have met on the pitch to battle for territorial respect and Pacific Northwest dominance. Though the kits have changed, the intensity of this epic rivalry between the neighboring clubs and their passionate and unruly supporters has not. Drawing on interviews and deep research, veteran sportswriter Geoffrey C. Arnold takes a behind-the-scenes look at the villains and champions, chants and tifos, bragging rights and blowups that define this feud. Join the March to the Match and celebrate with chainsaw antics as "Cascadia Clash" chronicles the Flounders versus Portscum tradition from its 1975 beginnings in the North American Soccer League to its current status as Major League Soccer's greatest grudge match.