Sometimes you have no control over things and you simply have to go with a gut feeling. The weather maps didn't have a single cloud within a 300 mile radius of the park this evening but about 3 hours before dark...I had a gut feeling about this location I had seen earlier in the week. Decided to make the drive and got there an hour before good light. Didn't see a cloud the entire time....that is right until the sun was perfect for some afterglow and Mother Nature sent me this one line of clouds racing over head. I didn't even use an ND filter for the cloud movement they were moving so fast. Had time for 3 shots...then they vanished as quick as they appeared. Looked around and not another soul was there to see it either. :) Gotta love moments like that.