If the nuclear reactors in Japan meltdown, will the fallout reach the Western United States?

After hearing that the reactors of the plants were beginning to meltdown, I got a bit nervous hearing this. I know the Western States wind current comes from Japan and Australia. Would most of the Nuclear Waste get absorbed into the ground, or would it travel to the US and cause a big catastrophe? Wouldn't the Pacific Ocean current bring radiation to the west coast? I recall that some balloon bombs that were dropped in the South Pacific during World War 2 ended up catching a wind current and traveled all the way to Oregon in 10 days, but balloons are made to fly, so maybe that helped them travel farther?