[moopogyOvenny]

Thanks for that explanation; the same happened here a year or so ago. and yes, it was a very loud 'gunshot' sound and bits of glass went everywhere and even 'ricocheted' well out of the bathroom.
I was outside and was glad I had been.
I never understood how it was or could have been caused.

Glass is interesting stuff which I am sure we have discussed on many levels before.

One day which happened to be my son's fourth birthday when we had just moved into this house newly built. We were doing lego train set on floor when..
The front yard was empty, because the builders had needed the space. A willy willy hit. A big one.. I sat immobilized the windows bulged. they were just about to snap and spray, when they snapped back to reality plane and just quivered. The room was suddenly full of dust.