As the annual Geminid meteor shower dazzles with its display, a meteor exploded over Arizona, rattling windows. It was unlikely to be a Geminid as it was moving at about 45,000 miles an hour, much to slow to be one of the fast moving Geminids which average about 78,000 miles an hour.
This was a big one, weighing in at about 100 pounds, it was a good sized chunk of space rock. (source)
Dr. Vishnu Reddy explains what happened: