Exploding Side Glass

or a rock? glad you're okay! you have questionable neighborhoods by the sea?

 

Maybe a BB, pellet, or ball/rock from a slingshot? If velocity was low, it could've shattered the glass, but bounced back and not end up inside the vehicle.

At least no personal injury resulted. Glad you came out relatively ok.

 

Wow, that is horrible! Thankfully it didn't cause you to have an accident. What a crazy thing to have happen. Sad to think that some kids would do such a thing and think it was "fun". Bizarre world.....

 

Was there any traffic on that side of the car? If not, was there a sidewall or barrier for a rock or other road debris to bounce from?

Last year, the driver side wing window of my Forester exploded on I-70 in Colorado, moments after I saw and shifted away from a pair of rocks (large baker potato size) that fell off a passing flatbed truck and bounce from the lane stripes up to my eye level. Part of the mirror housing also shattered, it probably deflected the rock towards the window. The timing of the visible rocks wasn't quite right, so it was probably an unseen third rock. The rock itself did not enter the car, but some fragments took a few paint chips off the A pillar.

 

Remembering that all auto glass is tempered, ANY flaw in the glass (you won't see them), or a tiny scratch (you can usually see that if you look carefully), will concentrate the strain at that point. Eventually it will release explosively.

Windshields are two layers of tempered glass with plastic in the middle to hold it together if/when it fails.

If you have polarized sunglasses have a look at the windows. You can actually see the strain tempering imparts. Tempering imparts a very high resistance to failure, but not a total resistance. It also ensures the glass will fail to very small pieces, usually small enough they can't kill you.

It could have been -something- thrown, either by someone or another vehicle, or it could have just been time. My experience (observation) is failure is rare, but does happen.

DO have a close look at the gap where the seat back and seat bottom come together. Often tiny pieces of the broken window hide in there and slowly cut the material.