Got Normandy and read the rules. Small question, is there any way for craters to appear on the board other than the scenario setup? I was actually hoping that the craters came with the rules of when they are created, it would add a new tactical depth to the game.

Then again, a cratered terrain means it was a target of very heavy bombardment, and other than a bombardment card none of the units in the game so far have enough firepower to make a hex so cratered that movement becomes a real problem in there.

I guess there probably is not any explicit rule stated in official rules that would "create" crater tokens on a map of a scenario.

I sometimes use them (in my own scenarios) as a result of certain Artillery or Air bombing cards, which would score certain number of hits on a hex.

Some scenarios state in their special rules how craters appear, e. g. after a successful Naval Bombardment in that hex during the game. If a scenario does not mention this => no craters for you. Of course you can houserule this, like Artemis does.