Though much has been made of the trash from the 2011 Japanese tsunami that has since washed up on beaches in Alaska and the Pacific Northwest, it's likely only a fraction of what's still adrift in the Pacific Ocean. On Sunday night, the Coast Guard in Seattle warned that one such drifting piece of debris could pose a threat to vessels in the region.
The Coast Guard says that the fishing vessel Lady Nancy spotted a large dock floating about 16 miles off the Washington state coastline on Friday. Crew aboard the Lady Nancy took a photograph of the dock, but it hasn't been seen since, in spite of a search that eventually spanned more than 300 square miles. The Coast Guard has also been broadcasting a warning to mariners in the region.
Much of the trash that has come ashore after the 2011 tsunami so far has been small, though there has been a lot of it. Things like wood, buoys and plastic have piled up on beaches from Oregon to the Southeast Alaska panhandle and the Gulf of Alaska.
There have been exceptions, though -- a dock washed ashore on an Oregon beach in June. A shipping container with an intact motorcycle inside was discovered in British Columbia. And perhaps the largest piece of debris, the derelict Japanese fishing vessel Ryou-Un Maru, was sent to the bottom of the ocean 180 miles off the Alaska coast by the Coast Guard.
Such sizable chunks of tsunami trash are rare, however. The majority of debris has already sunk, according to the Coast Guard and the National Oceanic and Atmospheric Administration, and the rest is spread out over an area of ocean three times the size of the Lower 48 states.
Keeley Belva, a spokeswoman with NOAA and the marine debris program, said that the dock in Oregon and the B.C. shipping container are certainly among the largest debris that has been reported and confirmed as the result of the Japanese tsunami.
"Those are the the big things that we've been able to confirm as debris from the tsunami," Belva said. "There are still about 1,400-ish reports of possible debris, but without any identifying information on them, there's no real way to tell if that debris is from the tsunami."
Also reported was another dock spotted off the coast of Oahu in Hawaii, and now the dock drifting somewhere off the coast of Washington.
And then there are the objects that haven't made widespread news, like another shipping container that's washed ashore in Alaska, between Cape Suckling and Kayak Island in the Gulf of Alaska. That's according to Chris Pallister, president of Gulf of Alaska Keeper, an organization that spends summers surveying and cleaning up Alaska beaches.
Pallister said that he wasn't able to confirm the container was from the tsunami, but was able to view it from the air while surveying for debris.
"We just flew over it a couple of times, because the beach was so crappy we couldn't land there -- we were in a wheel plane," Pallister said.
He said he also spotted another, smaller shipping container on an Alaska beach over the summer, and a sizable coil of high-density natural gas piping. Despite the busy waters of the Northwest, these large objects have often arrived completely unannounced and unseen prior to landfall.
Part of the worry then becomes that these large pieces of marine debris could damage a small vessel that strikes them -- or even a larger ship traveling fast enough. Pallister said that such an incident was a valid concern.
"I think it could hurt a big boat," he said. "But it would definitely be enough to sink a small boat."
Hence the warning from the Coast Guard about the recent sighting off of Washington. NOAA's Marine Debris website says that the Coast Guard may respond to debris that poses a hazard to maritime shipping lanes.
Still, the real threat may be beaches growing increasingly choked with smaller, more subversive debris. Pallister said that the beaches are already worse than he's seen before, particularly the ocean-facing beaches of Kayak and Montague islands. Fortunately, help may be on the way; the Japanese have pledged funding to help clean up North American beaches, and $56 million in cleanup funding was inserted into a bill providing disaster relief funding in the wake of Hurricane Sandy earlier this year.
Contact Ben Anderson at ben(at)alaskadispatch.com