I'm just not getting this rule. I've searched a bunch through the forums and don't see anything. Can someone please explain how craters and debris are formed. Didn't see reference to them in the scenarios either.
They are formed by German artillery trying to level the city of Stalingrad...
This rule is simply meant to give the effect of a city that has been ground up by fighting. Normally, roads are -1 Cover and give +1 Movement point. In Stalingrad, this is not so, which reflects the presence of debris and craters that give some nominal cover from exposure.
There IS a rule for creating Rubble, which is a terrain type. See ST 1. But that's different from the game absence of roads because of ST 4.