[emmitt69]

A quick change in pressure will do it, a friend of mine that hauled cars had to roll the windows down a little in all the cars b/c when he would go through places like in Az. the windows would break in the cars if the pressure got too great. so it could very well be the weather that caused it.
Also, where did most of the glass go, inside the car or outside?? If more went in and all over the place in the car it was vandalized, if more is on the outside, or is not spead around inside the car as much, it had to be the pressure.