I've fiddled around a bit with the tiberium in my map, as soon as the snow disappears it grows rapidly. (No complaint, I love it

) Two quick questions, do the ion storms appear naturally already? And can tiberium crystals appear in a roofed cave or mountain? So far I've not seen a tiberium deposit appear in a roofed area.
And a little suggestion. If possible, try to make the tiberium spread underground aswell. Maybe with a scanner of some sort you can track it and with specialized tools you can get rid of it. I'd add more to the current crystals than "Oh its here, lets block it off and we're fine." And you have to try and destroy it otherwise its going to get out of hand quite quickly. Again, just a suggestion. Not sure if Rimworld allows things to be placed above the bedrock and below the ground.