Keary Sorenson routinely finds garbage clearly linked to Japan and many other Asian countries while conducting cleanups along the Sonoma County coastline.
But the 59-year-old Sebastopol resident is still looking for his first example of debris from the 2011 Japanese earthquake and tsunami, despite months of patrolling Salmon Beach for signs of fallout from the disaster.
Experts say it's hard to predict when or even if significant volumes of tsunami debris will find their way to California.
"What we're going to see from the tsunami, we're really not sure," said Rick Hanks, who is retiring as manager of the California Coastal National Monument overseen by the Bureau of Land Management.
Sorenson is among 12 local volunteers taking part in a federally managed effort along the west coast to watch for debris from the powerful tidal wave amid the tons of other marine garbage that comes ashore.
A half-dozen potential examples found on the Sonoma Coast and reported to the National Oceanic and Atmospheric Administration have not had the kinds of unique markings needed to confirm their origin, officials said.
But a 21-foot panga boat that washed ashore near Crescent City last week has been linked to a high school in the hard-hit coastal Japan city of Rikuzentakata. It is expected to be the first verified tsunami artifact to have reached the California coast.
Japanese officials estimate the 2011 inundation swept 5 million tons of debris into the ocean. About 70 percent of it sank off-shore and 1.5 million tons spread into the ocean. But it's unclear how much is still circulating, let alone anywhere near California, NOAA personnel say.
Buoys and bits of Styrofoam that have turned up in Hawaii and Alaska are believed to have originated with the tsunami, though only some are identifiable.
Sorenson and his wife, Sally, head once a month to their assigned portion of Salmon Creek Beach for a geometric survey to document what they find. Twenty-six sites in California are being monitored.
Part of the two-year mission, which begun last year, is to establish baseline patterns for debris deposits on the coast to help determine if a spike in detritus might signal the arrival of tsunami debris.
Bodega resident Cea Higgins, volunteer coordinator for Sonoma Coast Surfrider and local coordinator for the tsunami debris monitoring effort, said she has 12 reliable volunteers, though she's looking for help on the coast between the Russian River and Gualala.
A large part of the focus is to prevent invasive species from coming ashore aboard debris, but Higgins and Sorenson said they are motivated to do what they can to limit pollution and safety hazards along shore.
Higgins said she's also lobbying hard for better statewide coordination, like standardized signage that would inform the public what to do if they find suspected tsunami debris.
And she worries - despite government assurances that any tsunami debris shouldn't bear contamination from a Japanese nuclear plant meltdown caused by the quake - that volunteers don't have equipment to check for themselves.
"What we're advocating for at Surfrider is a more established and uniform protocol for the state of California that trains volunteers about possible hazards on materials, that trains volunteers about what to do with large (debris) pieces, but that also sets up some kind of signage if you're in the public and you come across these items," she said.
More information is available at www.marinedebris.noaa.gov/tsunamidebris or www.scsurfrider.blogspot.com.
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