I finally visited the dam last Friday. It's amazing. The cracks in that video are minor compared to others on the top and side of the dome. There's a lifeguard platform on a 1-ft thick slab that's uplifted about a foot forming a bridge you can look under. I haven't downloaded my pictures yet, I've been at a conference in San Diego, but I probably have some good ones to upload.
Here's another video from a distance that gives a better sense of the magnitude of the big events - there have been 4 big cracking events so far, and lots of minor events including one while I was there.
Skip forward to 1:09 where it sounds like thunder going off.
