Clue one is a stationary police car at the Futaba intersection, an unusual occurrence:
Clue two is the ship that was in the Fukushima port yesterday and today. I would post a screenshot but my blog is limiting me more than usual today. (You can see the screenshot of the ship from yesterday's post).
Clue three is the flashing light that warns drivers of something, I know not what, as they drive to the Fukushima site. I can only post a few screenshots so I'll skip the flashing light shot.
Clue four is the heavy emissions visible on TEPCO cam 1 but not cam 4: