ScienceDaily (Nov. 14, 2011) — A catastrophic landslide 22,500 years ago dammed the upper reaches of northern California's Eel River, forming a 30-mile-long lake, which has since disappeared, and leaving a living legacy found today in the genes of the region's steelhead trout, report scientists at two West Coast universities.
http://www.sciencedaily.com/releases/2011/11/111114152404.htm