The Guadalupe River has a history of significant flooding events, with major floods recorded in years like 1936, 1952, 1972, 1973, 1978, 1987, 1991, 1997, 1998, 2015, 2018, 2020, and 2021, with recent events in July 2025 causing significant impacts and fatalities. Notably, the 1998 flood is described as the most significant in recorded history downstream of the Canyon Lake Dam, and the 2002 flood is the only one to overflow the Canyon Lake emergency spillway. The Guadalupe River in Seguin, Texas, is recognized as one of the top three most dangerous rivers in the state for flash floods.