18' - expect major widespread flooding of homes and structures from the City of Tualatin downstream to the confluence with the Willamette, along with numerous road closures. Also expect major flooding of homes and boat houses around Lake Oswego and along the Oswego Canal.
17' - expect flooding of numerous homes and structures along the Tualatin River upstream of the City of Tualatin down to the confluence with the Willamette, including flooding of homes in the Rivergrove area just east of I-5. Also expect overtopping of the Oswego Canal inlet gate and flooding along the Oswego Canal. The Oswego lake surface will begin rising even with all lake outlets fully opened.
16' - expect flooding of numerous homes and structures along the Tualatin River upstream of the City of Tualatin down to the confluence with the Willamette, along with flooding of homes in the Rivergrove area just east of I-5. Overtopping of the Oswego Canal inlet gate is possible at this level, which would lead to some erosion of the canal banks.
15' - expect flooding of homes and other structures to begin along the Tualatin River from upstream of the City of Tualatin down to the confluence with the Willamette. Also expect several road closures in the area.
14.5' - the Oswego canal inlet gate will likely be overtopped. Expect several road closures in the area. Flooding of homes and other structures along the Tualatin River from upstream of the City of Tualatin down to the confluence with the Willamette will also begin.
13.5' - expect lowland flooding. Numerous secondary roads upstream of Tualatin are likely to be closed, and low-lying structures along the Tualatin from the City of Tualatin downstream to the confluence with the Willamette are threatened by flood waters.
11' - some localized lowland flooding is possible.