The track had recently been smoothed - made it too fast for the geometry. NASCAR seems to believe that the teams were underinflating the tires in an effort to get more traction, but that was causing the tires to overheat. That caused the blistering and popping problems.
IIRC, the track owner promised to have it resurfaced before the next race to prevent this from happening again.
Sounds like NASCAR needs to set some standards for track quality and road surface conditions. If the State DOT can do it, surely NASCAR can do it...........