This kind of reminds me of the old TG 0.x images that used to do the rounds so that's why it's called retro, nothing more.
Localised clouds with 'ray traced shadows' and RTA rendered too. The clouds follow the river through some funky new cloud masking with the terrain shaders. The river isn't as visible as I'd planned because of the angle of the light but, meh, only took a little over half an hour to render so, I might do it again later, I'm sick of it now, this is my second 'final' render since opening the project today.
Terrain is a general TG alpine fractal base. I've saved it as a .ter after generating it as a heightfield for quick rendering and, to use again, I quite like it.
Wish I'd used more soft shadow and atmosphere samples, I lowered the atmo samples a bit much for this one.
[attach=#]
Cheers for looking!