34' - expect flooding of much of downtown Vancouver, along with major flooding along the Columbia River from Vancouver downstream to Woodland along the Washington side and Portland and Sauvie Island on the Oregon side. Some lower levees may be overtopped.
31' - expect major flooding. Overtopping of some lower levees is possible. Expect widespread inundation along the Columbia from Vancouver downstream to Woodland on the Washington side and Portland and Sauvie Island on the Oregon side. Tributary rivers will be backed up. Port operations and ship traffic will be affected.
30' - expect widespread flood inundation along the Columbia from Vancouver downstream to Woodland. Numerous islands and sloughs on the Columbia upstream and downstream of the I-5 bridge are flooded. Many industries along the river have historically ceased operations at this level.
27' - expect widespread flooding of low lying farmland, islands on the river, and sloughs in the Portland and Vancouver area. Historically, river traffic has been halted to prevent water from overtopping the lowest dikes along the river.
24' - expect numerous sloughs to begin flooding in the Portland and Vancouver area. Numerous islands on the Columbia river both upstream and downstream from the Interstate Bridge have historically begun to flood at this point. Also expect flooding of parks and lowland areas near the Sandy River confluence above this level.
20' - expect widespread flooding of unleveed lowland and agricultural land, along with flooding of the access road under the north end of the Interstate Bridge. Islands on the Columbia downstream from the Interstate Bridge are threatened above this level. Access to parks, trails, and some house-boat communities in and near Portland and Vancouver will be impacted.
18' - expect flooding of property and farmland not protected by levees to begin. The main areas impacted have historically been from Sauvies Island downstream to Woodland. Inundation of parks and trails along the Columbia in and near Vancouver and Portland will continue. Access to some floating home communities may be affected.
17' - expect flooding of some lowland access roads, parking areas, and trails on Sauvie Island, around Vancouver Lake, and other parks and trails along the Columbia in the Portland / Vancouver metro area. Access to some house-boat communities is impaired.
16.5' - expect flooding of several parks along the Columbia River in Clark and Multnomah Counties, including Capt William Clark Park in Washougal, areas around Vancouver Lake, and trails along the Columbia River. Low areas on Sauvie Island and Government Island are flooded. Boaters should be aware of faster currents and more debris than usual in the river.
16' - expect flooding of some islands and low areas, with minor impacts for parks and trails along the river.