the plume from Dai-ichi
Toronto, 2011.03.18
Here's a map of the radioactive plume coming from the Dai-ichi plant in Japan. Thanks to Brian.

It's interesting to see how this going. The quantities involved are hard to put into context, but I get the impression that the story would be very different if this reactor had been somewhere upwind of Japan's major cities, such as in the Fukuoka area.