Less than a year ago, land conservation organization Forterra drew accolades for buying a 40-acre parcel near Hamilton . The move was celebrated as a first step toward relocating the town to an eco-friendly village. Hamilton’s houses and their septic tanks, it seemed, were finally making way for good sense and spawning salmon: Conservationists argue that habitat restoration on the Hamilton floodplain could boost the dwindling Chinook runs here, though critics counter that would take decades.

Hamilton’s enhanced flood risk is a unique product of geography and atmosphere. A band of moisture in the sky known as an “atmospheric river” forms over the Pacific Ocean. Thousands of miles long and hundreds of miles wide, the bands collide with the Cascades. When that happens, a phenomenal amount of water is forced through the narrow valley in which Hamilton sits. During the last major flood, in 2003, 1.2 million gallons of water flowed through the town each second. Built on the inside edge of a curve in the Skagit River, Hamilton is squarely in the path of least resistance.

State emergency managers and the Union of Concerned Scientists suggest Washington will see extreme storms more often as the climate continues to change. Washington rivers are expected to flood more often in the winter and less often in the spring.

Whether climate change will increase flood intensity on the Skagit River is still something of an unknown, said Mark Mastin, a surface water specialist with the U.S. Geological Survey’s Washington Water Science Center. But all indications are that more rain and less snow will mean more flooding west of the Cascade curtain.

“You would expect more precip during the winter as rain, and that's when we get our floods,” Mastin said.