The National Weather Service in Portland issued Wednesday afternoon a flood warning for the Columbia River in Clark and Multnomah counties, and said to expect possible high water through the night and until further notice.
The weather service said the river was forecast to rise above flood stage, 16 feet, around 5 a.m. Thursday. Forecasters said to expect crests near 16 feet 4 inches during high tide Thursday and Friday mornings.
River levels will likely fluctuate a few inches above or below flood stage through Friday, and there is potential for levels near or above flood stage for several days.
Amanda Bowen, a meteorologist at the weather service, said the flooding could last for a few days to a few weeks.
“We’re not expecting any major flooding or anything like that,” she said. “It’s really going to hover kind of around that lower flood stage.”
According to the weather service, there could be some flooding of islands and low areas in and around the river, with minor impacts for nearby parks and trails.
Water managers upstream have been adjusting the volume of water released from and stored behind regional dams throughout the Columbia River Basin to manage the increased flows.
This has created problems for parts of Washington, western Montana and British Columbia, where evacuations are ongoing and emergencies have been declared. In some areas, rivers are expected to remain above flood stage for days, if not weeks, as the snowmelt continues.
Bowen said melting snow due to warm temperatures means more water in the river system. Ongoing flooding has prompted evacuations and damaged homes in Northeastern Washington, Montana and British Columbia.
“There’s a lot of water coming through the whole Columbia system right now,” she said. “They’re having to make a decision basically at every single dam upstream all the way up to Canada on how much water they’re going to let out.”
Also, forecasters said, boaters should be aware of faster currents and more debris than usual in the river.
