I arrived at the Great Saskatchewan Sand Hills in mid afternoon. I walked about a couple of the dunes making images here and there. I returned to the van after a couple of hours to rest waiting for the evening light. Shortly after, clouds rolled in and it looked like it would not clear that evening. Still, I walked about an hour before sunset, waiting, hoping. Just before the sun would sink below the horizon, the clouds broke just enough to allow strong dramatic light to bathe the landscape and, in particular, the swirls of clouds above.
The color contrast between the warm and cool colors makes this composition. The small dark tree on the right balances the larger bright sand dune to the left. While the clouds are actually moving from right to left, the movement in the frame is going in the opposite direction. These dramatic moments are often short lived and you end up working very quickly and from instinct.