The beaches between Coos and Winchester bays might collect more tsunami debris than other Oregon beaches this summer, according to researchers at Oregon State University.
The predictions are based on knowledge of ocean currents, said Jack Barth, an OSU oceanographer who studies currents.
“Ocean currents do sweep close to shore north of Coos Bay,” Barth said.
Scientists still don’t know how much debris will wash ashore along the West Coast in the coming year, but the arrival of a large floating Japanese dock on Agate Beach near Newport this month — torn loose from a harbor during the 2010 tsunami — has everyone speculating.
During the summer, ocean currents on the West Coast run north to south, driven by summer winds, Barth said. Although the Oregon coast is basically straight, offshore there’s an underwater bank — called Heceta Bank — that begins just north of Florence and ends near Winchester Bay. The bank forces the currents offshore at Florence, then propels them back toward shore near Winchester Bay. Any debris that is caught in the north-south current north of the bank has a higher chance of landing south of Winchester Bay where the current juts toward shore, Barth said.
The National Oceanic and Atmospheric Administration estimates that 1.5 million tons of tsunami debris could wash ashore in the coming years. Ocean currents will likely carry much of it toward northern Washington where it will enter the southerly currents this summer.
But after the summer months end, Oregon will likely see much less debris, Barth said. Ocean currents switch and run from south to north during fall and winter, driven by heavy winds from the south, Barth said. So the bulk of the tsunami debris that arrives after summer will be pushed north toward Canada.
Ocean currents in general run far offshore, which means much tsunami debris might never land, said Jamie Doyle, a sea grant extension agent with the OSU Extension Service.
One of the major concerns with tsunami debris is its potential to bring invasive foreign animals and organisms to the West Coast. Early fears that debris would be radioactive have proven false, but scientists continue to identify potentially invasive organisms attached to the floating dock near Newport.
“The floating dock can be considered a wakeup call that conveniently arrived on the beach within five miles of a leading marine science center,” Jessica Miller, an OSU marine ecologist who was one of the first scientist to examine the organisms, said in a news release. “This provides us with a spectacular opportunity to understand the overall invasion process and the risks associated with tsunami debris fields to come.”
According to the release, the Northern Pacific seastar, the Japanese shore crab and a species of brown algae came attached to the dock and have a high potential for successful invasion. Fifty other organisms have been identified on the dock.
The Oregon Department of Fish and Wildlife leads the state’s response to the invasive species threat.
Doyle said general tsunami debris removal is being coordinated by Oregon Parks Department, which should release a comprehensive response plan sometime in July.
Reporter Jessie Higgins can be reached at 541-269-1222, ext. 240, or email@example.com.