The threat to the B.C. shoreline from Japanese tsunami debris is over, says Jan Hafner, a researcher at the International Pacific Research Center at the University of Hawaii.
B.C.’s shoreline and beaches were expected to be hit with everything from corpses to radioactive material coming in with the tide, but have seen much less debris than anticipated.
The March 2011 tsunami, the result of a devastating 9.0-magnitude earthquake, swept an estimated five million tonnes of debris into the ocean. About 70 per cent was believed to have sunk off the Japanese coast, leaving about 1.5 million tonnes floating in the Pacific Ocean.
Some items, such as wooden docks and Japanese fishboats, were pushed by eastbound winds onto the west coast of North America.
While a number of larger items have reached B.C.’s shores — including a 60-metre fishboat spotted off Haida Gwaii in March 2012 and motorcycle in a storage container that washed ashore a month later — much of the debris has been smaller pieces of plastic, Styrofoam, wood and fibreglass.
The bulk of the debris field, estimated to be the size of California, was predicted to hit North American shores this year.
But those predictions appear to be off. Floating debris such as lumber from buildings has either already made landfall or will be swirling in the ocean indefinitely, Hafner said.
“Right now, the story for the west coast of North America is the tsunami debris is more or less over — they will receive not much more,” he said.
It’s good news for Tofino Mayor Josie Osborne, who walks the beaches near her home every day.
“Honestly, I’ve been waiting to see a pulse of material come forward, but it just hasn’t,” Osborne said. “I suppose it’s good news for us, but obviously not good news for the ocean.”
Much of the debris is trapped in the North Pacific gyre, a system of rotating ocean currents that also contains the Great Pacific Garbage Patch, Hafner said.
When debris is spit out of the circular currents, it usually goes toward the western Pacific and Southeast Asia, he said.
The last of the significant debris to go by Hawaii was lumber that floats low in the water and is moved by ocean currents rather than wind, Hafner said. “In autumn of 2013, we started to see the wood pieces and we expected that would be the last wave of tsunami debris from Hawaii.”
Osborne finds comfort in confirmation that the threat of the tsunami debris is over. “The District of Tofino is certainly prepared if we did get a big pulse of material coming ashore,” she said.
“We’re very fortunate that we have so many visitors that care about the place and local residents that like to get out and remove things.”
