The New York Times reported earlier today:
A United Nations forecast of the possible movement of the radioactive plume coming from crippled Japanese reactors shows it churning across the Pacific, and touching the Aleutian Islands on Thursday before hitting Southern California late Friday.
The Times was quick to lessen the impact of any radiation reaching the United States:
Health and nuclear experts emphasize that radiation in the plume will be diluted as it travels and, at worst, would have extremely minor health consequences in the United States, even if hints of it are ultimately detectable. In a similar way, radiation from the Chernobyl disaster in 1986 spread around the globe and reached the West Coast of the United States in 10 days, its levels measurable but minuscule.
This begs the question, if low levels of radiation can reach the United States from the radiation currently being emitted by the damaged reactors, what happens if the radiation level increases dramatically? With confirmation that the spent fuel pool at Fukushima Unit 4 has boiled dry and the chances increasing of a major release from that pool, shouldn’t we be at least a little worried about fallout? There seems to be reason for concern in the Times article:
The projection, by the Comprehensive Test Ban Treaty Organization, an arm of the United Nations in Vienna, gives no information about actual radiation levels but only shows how a radioactive plume would probably move and disperse.
The forecast, calculated Tuesday, is based on patterns of Pacific winds at that time….
And, of course, there is no reason to believe that the plume would not reach past California:
The forecast assumes that radioactivity in Japan is released continuously and forms a rising plume. It ends with the plume heading into Southern California and the American Southwest, including Nevada, Utah and Arizona. The plume would have continued eastward if the United Nations scientists had run the projection forward.
Here’s a link: http://www.nytimes.com/2011/03/17/science/17plume.html