Two-and-a-half years after an earthquake and tsunami devastated parts of Japan, suspected debris from the disaster continues to quietly wash ashore in Hawaii and along the West Coast of North America.

Officials in Hawaii have confirmed seven items of tsunami debris this year alone, including a blue plastic bin that had a live bird inside. In Alaska, Chris Pallister reports his group, Gulf of Alaska Keeper, has picked up a quarter-million pounds of debris during this soon-to-end cleanup season, a function largely of additional funding. The most his group has picked up in any other year is about 160,000 pounds, he said.

Not all of that is tsunami debris, which is very tough to distinguish from run-of-the-mill marine rubbish that’s been a long-running problem in coastal areas without clear, identifying markers - like a serial number or name.

But Pallister believes given the difference in volume and type of debris that his group is seeing, a significant percentage is from the tsunami. He said this is a “slow-moving environmental disaster,” with long-term impacts that will be hard to quantify.

“But when you go out there and walk down those shorelines and see billions of pieces of Styrofoam ground up all over and plastic everywhere, you know that it is a disaster,” he said. “My greatest concern is people have lost track of this and they don’t understand how bad it is.”

Even before the tsunami, Alaska, with its vast coastline, received a lot of debris, and that trend has continued, said Peter Murphy, a regional coordinator with the National Oceanic and Atmospheric Administration marine debris program.

Other states and Canada are having different experiences.

In Washington, for example, the last piece of identified tsunami debris was from April. Officials there credit the lack of tsunami debris to ocean currents and wind. In Oregon, calls to a marine debris hotline are only averaging about one a day.

NOAA gave each of the five West Coast states $250,000 initially from a $5 million gift from the Japanese government to clean-up debris. Oregon hasn’t spent that money yet, though state parks spokesman Chris Havel said officials are stocking up on supplies and preparing for this fall and winter, when more debris is expected.

Eben Schwartz, marine debris program manager for the California Coastal Commission, said the issue is somewhat fading from the public’s mind. While there were congressional hearings and national news stories on tsunami debris last year, he noted that it’s been a while since a huge dock has washed ashore, as happened in both Oregon and Washington in 2012.

“The big items that wash up are the ones that tend to garner the most attention, from my experience,” he said. “But what we’re finding is that, we’re finding items that are likely tsunami debris along our coast, especially along the north coast of California. We have been seeing more of it over the course of the year and we expect more to wash ashore in the winter months.”

Here are three things to know about tsunami debris:

• Of nearly 1,900 reports of suspected tsunami debris, only about 35 have been confirmed, according to Murphy.

• It’s not clear what’s still out there and what will arrive, when, though items are expected for years to come. Objects spread out over time, and Murphy said officials aren’t looking at one solid debris field.

• Officials are looking at data to understand trends and to help prioritize efforts and better understand the impacts.