Awesome! I had been working on a similar project couldn't figure out the snow on the trees for the life of me! It's great to see how you approached it. The work look great! Thanks for sharing your process.
I believe author would be surprised that it's not american, but soviet bunker :)
Check out a nice work by Sephiroth Art called “Falling Star”.
Nice technique here, right? Actually, you can try creating your own art full of stars with the help of some free brushes from the artist.
The artist decided to release a new brush set on Gumroad to help young artists and to promote his work.