There's already a map called thunder. You'll have to rename yours.
Also, you'll need to make the map filename all lower case for compatibility with Linux. Construction seems pretty clean, but you need to work on making the rocks a little more natural. They're all thin, flat, 90 degree angles. Adding a few brushes and using clipping planes to create more natural angles can do wonders for the believability. Alternatively, you might use a different texture -- something that fits what you've built a little better.
You might want to make some fence posts or something to make that chain link fence area look more natural as well.
* jitspoe shudders at the thought of a map worse than blitz.
