15 hours?? Wow, that's good!
I like this image a lot. If I remember correctly you posted this image first in black&white, isn't it?
The colors are splendid
Nice clouds and yes they're a bit grainy and I think increasing the atmospheric sample might help some too.
The terrain looks good and I like the subtle use of populations. It doesn't distract or draw too much attention.
How did you do the snow? Favour depression effect? I like how you've managed the snow's coverage.
I think you could next time try for a bit better composition by tilting the camera a bit upwards, because the composition is almost 50/50 and therefore not really interesting.
However, I can clearly see you did this intentionally because you wanted to catch the whole reflection of the mountain in the water
In overall very good work and nice to see something again from you, has been a long time ago!
Martin