This moment is a very good example of what Environmental Photography means, and how it differs from conventional landscape photography. The images have a depth of meaning that is subtle yet important, and very well worth looking for, and learning from.
30 minutes before this image was caught, this is what the view looked like....
I waited 3 hours in total, sopping wet and horrid, a drenched landscape. No evidence whatsoever of what was about to happen.
Conventional photographers would have been on the way down by then, these are dangerous hills, and in such wet conditions it is important not to get caught after darkness. This overcast cloud, would have looked like a no show. But before I went out I had checked the sattelite images for the day and it had shown clear air to the Northwest, where the sun would set.
Critically, this was the first day of transition from Low to High pressure systems and that makes for very rapidly dying thermals, as the energy from the sun decreases at nightfall.
A quite magical transition occurs over a very short period of time.
The clouds fade and the sky becomes clear.