I was out of town for over a week and couldn't watch the webcams. However, I've seen plenty of ugly looking screenshots posted by Enenewsers over the last week in the webcam discussion forum here.
I had a chance to view for myself today Fukushima steaming away.
Close-Up of Unit 3, which appears to be glowing in the shot above
I don't know what extent atmospheric conditions contributed to this steam. I do know that the steam was full of flickering colors and spark-like-phenomenon.