The lower and middle sections of the Klamath River are vulnerable to flooding, and major floods have occurred in years where major flooding has taken place in Northern California, particularly in the wake of Pineapple Express storms that bring large amounts of warm rain to Northern California. Fort Ter-Waw, located at what is now the town of Klamath Glen, was destroyed by the flood in December 1861 and abandoned on June 10, 1862. Other significant floods on the Klamath River have occurred in 1926–1927, 1955, 1964, 1997, and 2005, in several cases changing the course of the river. The Christmas flood of 1964 was particularly devastating. The Klamath River reached flows of ,