Clouds are a landscape photographer's spice to add flavor to their images.  Don't believe me, do a google on "Ansel Adam on cloud" and see how many hits come up of his images that have "cloud" in the name.  

My point is this,  There are a lot of good images that have a bright blue cloudless sky.  There are many more "great" images of the same location that have clouds in the sky!  I love the Owens Valley, it is gorgeous.   That said, would the above image be so moving if it did not have those wonderful clouds in the sky? I think not.