In the months after the tsunami, OSCURS (standing for the computer program known as the Ocean SURface Current Simulator), as well as independent simulations from the University of Hawaii, showed the main debris field covering an area the size of the state of California. It’s not a continuous island, in my estimation, but individual items as well as floating islands perhaps a few hundred feet across. By October, the prevailing winds and currents had pushed the field’s leading edge, the flotsam closest to America, half way across the Pacific to a position north of Hawaii.
In my November 2nd lecture, I reviewed the historical debris which had drifted from Japan across the North Pacific (see www.flotsametrics.com). I divided the flotsam drift into three geographical patterns: 1) Directly across the Pacific to North America; 2) Across the Pacific without stranding in America, looping south into the Great Garbage Patch (beneath the high pressure cell of atmospheric pressure located midway between San Francisco, CA, and Hawaii); and 3) Around the North Pacific’s two great gyres returning to Japan (flotsam requires six years to loop around the Subtropical Gyre and / or three years to orbit the Subarctic Gyre).
As to the fraction of flotsam taking these routes, it is anyone’s guess. Nevertheless, I like to reason from hypotheses based on my flotsam experience. Firstly, I estimate that 25% of the flotsam will follow each of these three pathways, the fourth quarter sinking in transit beneath the waves. Second, there’s a rough rule that flotsam released in a gyre tends to stay in that gyre (akin to the rule for happenings in Las Vegas). The tub toys, for example, lost twenty years ago in the Subarctic Gyre (a.k.a., Aleut Gyre; January 1992), mostly stranded around Aleut gyre. The tsunami debris, too, also began adrift in the Subarctic Gyre, leading me to suspect that it will mostly wash up along the toy routes. That is, along the shore from southeast Alaska, west along the Aleutian Islands, further west to the Kamchatka Peninsula, and returning in 2014 to the tsunami coast.
On the computer with OSCURS, Jim had been charting the progress of the tsunami debris at monthly intervals when the US Navy updated its files of daily weather data. He’d simulated high-windage drifters, but not nearly as high as the windage of the following drifter. My review that chilly Tuesday evening in Ocean Shores included flotsam of varying windage. One flotsam, a Fish Attraction Buoy / Device (a FAD in oceanographic jargon), had drifted in 8.0 months from the tsunami coast to Copalis Beach, WA, not far from where I was lecturing. At 30 feet long overall, the cylindrical part measured 11 feet long by 47 inches in diameter, connected to a 7-foot mast. The waterline on the cylinder indicated that it sailed rapidly before the wind, explaining how it sped across the Pacific at twenty miles per day. Adding this transpacific crossing to the tsunami date of March 11, yielded November 11, 2011, an arrival to the week that I lectured in Ocean Shores.
On August 9, 2006, super typhoon Saomai tore the FAD free from its anchor off the village of Ginoza, Okinawa. On April 9, 2007, Kathy Klee reported the buoy off Copalis, Washington (see Beachcombers’ Alert, July-September, 2008). OSCURS revealed it had floated north from Okinawa to positions off the tsunami coast, then directly across the Pacific to Copalis Beach. With OSCURS, Jim computed the two windage parameters necessary for the winds and currents to drag the FAD across the Pacific three times faster than surface water.
OSCURS caused me to review many historical flotsam (such as small craft like a Boston Whaler) exposed above the waterline such that the winds sailed them at a speed similar to that of the FAD. It seemed reasonable that amongst the millions of tons of tsunami debris some of these high-windage drifters would be floating across the Pacific, including boats, houses, FADs and other large fishing buoys. This led me to ask Jim to run OSCURS with hypothetical FAD buoys launched along the tsunami coast.
With OSCURS, Jim launched six buoy tracks off the tsunami coast on March 11, 2011. Using US Navy data, the tracks progressed day-by-day across the Pacific until October 31, 2011, the last day that data were available. By Halloween, OSCURS indicated that five buoys (one headed into the Garbage Patch) had arrived in America from Washington State north to Southeast Alaska. During November and December, I conducted numerous media interviews, requesting beachcombers to report large debris which I thought should have arrived on American shores. By Pearl Harbor Day, however, none had been reported. Beachcombers as well as myself, however, did not know what specific flotsam to expect. That would soon change with Epiphany No. 2, also on a Tuesday, and stemming from other large fishing buoys.