We know there's a spiral path and there's a power plant in the northeast corner we can use as a guide for when to start heading south. If enough of it's still intact to be recognizable.

The extent of the tunnel damage seems too much for man-made. I'm just wondering what the hell is up with the ice wall covering half the buildings, but leaving places like downtown and the residential areas uncovered. I'm sure it's the 'maze' design, but why? Increased difficulty level and limited movement as we move forward?