An article has come out in Applied Radiation and Isotopes, Temporal variation of monthly 137Cs deposition observed in Japan: Effects of the Fukushima Daiichi nuclear power plant accident. It appears that monthly cesium-137 depositions in 7 Japanese locations dropped after March 2011, but started to rise again in November.
The third graph refers to resuspension of cesium by month. This refers to cesium deposited on to leaves and trees entering the atmosphere by fire, wind, etc. As you can see, this happens at low levels in November and December.
You might remember the situation in late October 2011 with Abnormal smoke from reactor 2. This was followed shortly by 110 micro Sv/h in Setagaya may be caused by a flown piece of control rod. In Setagaya, Tokyo, not only was there very high radiation detected, but europium-152 was found, which could only have come from a piece of control rod, criticality event, or nuclear explosion.
And this entry for November 1, Breaking News: fission restarted at reactor 2. Xenon was detected (as also happened recently), which confirmed fission was occurring. Of course, Tepco denied it and said it had something to do with curium (which is no picnic either).
In November 2011, the IAEA stated that iodine-131 was detected over Europe (blamed on a Hungarian lab), and in February 2012 they announced it was detected again over northern Sweden (also blamed on Hungarian lab very far away).
So it all adds up to a criticality, the effects being isotopes circling the globe for several months. This time period, especially November thru January was subjectively bad for me, much worse than March-April 2011.