Rainstorms and warm temperatures in December 1861 combined with a well-above-average snowpack in the Cascades created the largest Willamette River flood in recorded history . An observer of the flood wrote , " The whole Willamette valley was a sheet of water " . From Eugene to Portland , thousands of acres of farmland were washed away , and many towns in the valley were damaged or destroyed . The " Great Flood " , as it is sometimes called , was massively destructive to human development because most of that development was located on the river 's floodplain , which provided rich soils and ready access to water transportation . The 1861 flood peaked at — more than the Mississippi River usually discharges in the 21st century — and inundated some of land . This flood destroyed the town of Linn City . When the flood ended on December 14 , only three homes remained standing in Linn City . No one died in the Linn City flood , but the destruction was too significant for the town to recover , and it was abandoned . Today the city of West Linn stands about where Linn City once was
Great Flood
Great Flood of 1862
Willamette River