The radiation readings over a large part of the US, especially the West, have been high lately. This is a result of the recent incident or continuing incidents at Fukushima Daiichi. I took a screenshot of netc.com at 2:30 this afternoon. And I selected a map of the dynamic tropopause for about this same time. The dynamic tropopause gives a good idea of the air masses over the US. This seemed to be the best fit of all maps to the radiation situation.
The purple-shaded areas on the second graphic show an air mass that originated in the Arctic. It is over the Great Lakes and Northeast. The wind barbs indicate the wind direction at the average altitude of 7,000-10,000 feet. The direction of the barbs show you where the wind is coming from. For instance, over Tennessee, the wind is from the west. Following the barbs, you can see the Arctic air mass has winds blowing from the far north. The rest of the country has winds originating from the Pacific.
The swirl over southern Nevada is low pressure, which is just swirling the contaminated air around. You can see that the high radiation readings on the seacoast of Virginia and North Carolina are now to the south of the boundary of the Arctic air mass. The jet stream roughly follows this boundary.
By Monday morning, Oct. 28, the Arctic air will move into the Rockies and northern plains, hopefully providing relief to these areas. But the clean areas now, like Indiana, Ohio, and Pennsylvania look like they will be in the soup. But, since the air takes longer to get into these areas, levels of short-half life radionuclides like I-131 will have dropped by then, so it may not be as bad as what is going on in the West. The west coast itself doesn’t look like it will have much relief.
This Japanese blog post states that, based on Tepco press releases, the amount of groundwater at the plant is now accumulating at a rate of 700 tons per day, which is 4 times the amount accumulated earlier. This has to do with the soil barrier they built. This will have to go into tanks or the ocean, or else groundwater levels will seep up into the surface.
And the “Blog of Waiting Chan” asserts from an embedded video that the recent gigantic increases in contamination of underground water, which have been attributed to leaks from the tanks, have actually been due to Tepco clearing debris from Units 1 and 3. This occurred August 12 through Aug. 19. Fukushima Diary confirms that the dust alarms from Unit 3 were going off at this time. The dust alarm was eventually turned off. Also radiation spikes occurred in Fukushima prefecture at this time, and it appears that a criticality occurred. Check out this nuckelchen video from Aug. 20.
So the surges in contamination would have been from heavy rainfalls swamping the piles of debris, wherever they put them, and releasing large amounts of cesium, strontium and tritium. And it is possible that Tepco caused the August criticality. Two typhoons are on the way to Fukushima Daiichi.