15 December 2011
Many variables affect whether and how long it will take debris from Japan to reach the U.S.
Image showing debris accumulated near the coast of Yamada, Japan following the tsunami. The debris has dispersed since this image was taken (Credit: U.S. Navy Pacific fleet).
For most areas it could be a matter of years, not days or weeks, before debris from the Japanese tsunami reaches the United States. The debris clumped together when it first washed into the ocean, but it has since dispersed, making it difficult to locate. This makes it hard for scientists to tell what types of debris are still afloat and how much of it will make its way toward U.S. coasts.
Scientists are relying on computer models to predict the path of the debris, but models can only assume general direction and timing. Since winds and ocean currents constantly change, it is very difficult to predict an exact date and location for the arrival of any debris on U.S. coasts without more information.
Models run by NOAA researchers and other scientists show some debris could pass near, or wash ashore, in the Northwestern Hawaiian Islands as early as this winter, approach the West Coast of the United States and Canada in 2013, and then circle back to the main Hawaiian Islands in 2014.
NOAA is leading efforts within the federal government — along with the U.S. Environmental Protection Agency (EPA) and other federal agencies, as well as non-governmental organizations and academia — to understand the nature and amount of items that may wash ashore.
NOAA is also working to understand the many possible impact scenarios and how to best protect our natural resources and coasts. It is considered highly unlikely that the tsunami-generated marine debris is contaminated with radioactive material because the debris washed out to sea before the release of radioactive water from the power plant. The EPA and the U.S. Food and Drug Administration are monitoring for radioactivity.