Green Bay fire officials say the historic blizzard in March likely contributed to a massive warehouse fire in Green Bay, though crews could not determine an official cause of the flames.The Green Bay Metro Fire Department says s now caused the roof of the north warehouse at Green Bay Converting to collapse on the morning of March 16. The fire began after that collapse, however, investigators were unable to identify an ignition source."The cause of the fire cannot be determined," Green Bay Metro Fire said in a statement. "However, the roof collapse significantly impacted the building's utility systems, which most likely contributed to the fire. The collapse also compromised the fire sprinkler system, preventing it from effectively containing the fire."It took crews multiple days to put out the flames.About a month after the fire, Green Bay Converting announced it was laying off "fewer than 35" of its 200 workers. At the time, the company said it expected full operations to resume this summer. ...read more read less