It appears that some sort of major steam event occurred at Fukushima Daiichi yesterday.
I posted screenshots and documented rising radiation levels at my blog (check last few posts).
The Enenews discussion forum has many links to screen captures from the various cams.
Here is one of the most powerful images, captured by Wotcha and posted here:
Also see evidence of yellowish emissions from the plant captured in screenshots from the Futaba cam: https://www.dropbox.com/s/4qe2f4hvpzhmx3z/YELLOW%20EMISSIONS%20FROM%20PLANT%20AREA%20April%206%202015.pdf?dl=0
Netc.com's radiation monitoring system indicated very high radiation levels, compared to normal averages, across northern Japan this weekend.
Radiation levels in Japan have been rising for over a week now and were episodically high throughout March according to Netc data.
The US is now experiencing a spike in radiation levels in the north east that coincides with a slow down in the jet stream volicity: