Blurry clouds

 

Some amazing clouds were visible in the late afternoon and early evening today.

I know the white clouds in the photo above appear to be out of focus, but that's really how they looked!  I'm not sure I've seen clouds like that before.  They were actually blurred!

Here's the sky about 5 minutes later (looking west from Bodega Head):

 

And a close-up of those blurred white clouds about 10 minutes after the first picture was taken:

 

I'd love to learn more about what causes those blurry clouds.  Does it have to do with temperature?  If you know what was going on, let me know!