Seems at the moment to be headed for the tip of the Aleutian chain.
The stuff headed for the West Coast is coming from lower down Asia.
Officials in Tokyo — 240 km (150 miles) to the south of the plant — said radiation in the capital was 10 times normal by evening but posed no threat to human health in the sprawling high-tech city of 13 million people.
Toxicologist Lee Tin-lap at the Chinese University of Hong Kong said such a radiation level was not an immediate threat to people but the long-term consequences were unknown.
"You are still breathing this into your lungs, and there is passive absorption in the skin, eyes and mouth and we really do not know what long-term impact that would have," Lee told Reuters by telephone.
Around eight hours after the explosions, the U.N. weather agency said winds were dispersing radioactive material over the Pacific Ocean, away from Japan and other Asian countries.