The Great Flood of 1894

In the early days of Portland, the Willamette Valley was a rather wild place. The forest was incredibly dense and the river untamed. The city of Portland, built among the stumps of trees close to the rivers edge, was inhabited by a bunch of hard scrabble pioneers, from lumber barons to low lifes, all trying to make a buck off of this rough, isolated land.

Portlanders lived at the mercy of the Willamette River. Some years the river was tame, while others it flowed wild over its banks and into the young city. The worst flooding in the city's history was 1894 when the waters rose up the the second floor of many downtown buildings and stayed there for weeks. The famous Erickson's Bar moved into a house boat then floated in the middle of Burnside Street. Shopkeepers built rickety bridges connecting each others stores. The residents of Chinatown partook in boat races along the flooded streets. 

From what I gather, Portlanders took the rising waters in stride (or in paddle, if you will). Shopkeepers and hotels didn't even think about stopping business. They just built walkways and false floors above the water. It's hard to imagine people handling a flood like this so well these days. It would disrupt running water and electricity in some of the cities poorest and fanciest neighborhoods - I'm sure causing the governor to announce a state of emergency. It is a distinct possibility that it could happen again. Dams built along the tributaries of the Willamette have greatly controlled the once untamed river, but every few decades the waters rise very close to the top of the seawall.