I was driving (in motion) with my wife and 5 children on a straight, smooth stretch (no curves or lane changes) of eastbound i-84 near burley/rupert, idaho. there was a light drizzle, temp of ~60 f, and no other vehicles within 300 feet front, side, or rear. all windows of the vehicle were closed, and interior temp of the vehicle was ~68 f. we heard a very loud, scary sound -- like a shotgun or as if we had driven under a huge waterfall. i looked around and saw no obvious issues, then looked up and opened the closed sliding sunroof cover. i found the sunroof had shattered, which scared me even more, and promptly closed the cover to prevent glass from falling on me, my wife, or my 1 and 3 y/o daughters who were seated in the second row. we stopped at the first available rest area to assess the damage and take photographs. as we drove, we heard glass continue to break off and both slide from the car roof onto the road surface, as well as toward the rear of the vehicle between the roof and headliner.