Fog VS Clouds

 We watch the clouds slowly come lower and settle in the mountain meadows and then they start to slowly spread out and move up the mountain to where we are. We can see them coming through the trees and then it gets really dense.  We let our three dogs out to go potty in the top photo and you really have to look to see all three. They are not fond of the clouds either because they can't see very far and don't feel safe.
In the bottom photo it shows our detached garage but it is pretty hard to see in the clouds. Just as suddenly as they lower down and settle in they raise up again and the air is clear. In lower elevations it is usually fog but in the mountains it is just the clouds passing through.