Picture your house and everything in it. Now picture it floating in the ocean. At last Saturday’s tsunami debris conference on Kauai, University of Hawaii researcher Dr. Nikolai Maximenko used that visualization exercise to give people a sense of what was washed out to sea by the monster waves that devastated Japan last March.

Some of that flotsam is expected to start washing up on the reefs and beaches of the Hawaiian archipelago, perhaps hitting Midway as early as next month, although, Maximenko said, it’s tricky to precisely predict.

There was more certainty in Dr. Henrietta Dulaiova’s assessment of whether the debris picked up any harmful radioactivity from the meltdown of the Fukushima nuclear power plant. “It is extremely unlikely,” the UH geophysicist said, noting that the radioactive plume initially released blew inland. And the debris pile was about 8 miles offshore last April when more than 10,000 tons of tainted water was released into the sea, where it was effectively diluted, Dulaiova added. Since then, contaminated water has been stored at the plant.

The conference, organized by Dr. Carl Berg of the Surfrider Foundation’s Kauai Chapter in hopes of developing a plan for dealing with the flotsam before it shows up, drew about 125 concerned citizens, fishers and ocean users. The Northwestern Hawaiian Islands, Kauai, Niihau and possibly Oahu, are most likely to be affected. Although no one knows exactly how much of the tsunami debris is still floating or how much will hit land.

Surfrider is trying to recruit more volunteers and enlist the help of local government.“We can’t put our head in the sand,” Berg said, noting that cleanup plans need to be worked out ahead of time,“and that’s now.”

To that end, Carey Morishige of the National Ocean and Atmospheric Administration (NOAA)’s marine debris program met with Kauai County officials on Friday, prior to the conference. The state Department of Health also sent a representative to the event, and is continuing to monitor the situation and develop a response plan.

Surfrider and NOAA are concerned that the debris, which could include 70- and 100-foot fishing boats loaded with gas and oil, may harm reefs, wildlife and ocean users. Morishige said NOAA has stationed observers at Midway and Laysan to watch for the debris

The stuff that initially washed out to sea has been greatly dispersed, Berg said. So unless the debris has wording linking it to Fukushima, like the small fishing boat found off Midway last September, or emits faint radioactivity, it will be hard to know if it was generated by the tsunami. But regardless of its origins, he said, if it poses a threat, it will need to be cleaned up.