If the glass is breaking into hundreds of pieces it is probably tempered safety glass and can spontaneously break. See the following link: http://www.glassonweb.com/articles/article/228/

We have lived in Central Minnesota over 60 years. Today we had a thermopane window 16 x 32 crack in half. For no reason. I have never heard of this except for mentions on this website.

It was -15 below at 6am and warmed up to -9 below at 1pm today when this occurred. No one was within 10 feet from the window when a loud BANG got both our attentions. We have no pets. And there was little wind outside.

The crack is a reversed C- shaped from the bottom left corner vertically to middle and the back to the same side upper left corner. The window is a white vynel type frame. Brand unknown. The window was made I suppose about when the house as built in 1996. This is a two level split entry.

With nature gas heat and the temperature inside is 63 degrees. There are no cracks in the house anywhere and the soil in the area is very sandy. No Clay. The sun was out but not yet shining in this portion of the house. This window in part of two siding windows. Both the same size mentioned above. These face west.

Also this window is not near a draft or heat source. Nothing fell on it. Located just below a double stainless steal sink. Which had no activity near it for hours.

Oddly two hours earlier I had taken a photo of the ice on the inside of this window. I laid a wooden 12 inch ruler against the window for a referance point for the height of the frost. ( about 2 inches )

The reason I did this was to show a home buyer that the ice on their window is sort of normal. I am a Realtor and I sold them a brand new house. And they called about frost on their windows in the new home.

I took three photos with my celphone with a flash. And emailed it to them.
Ironically the same window broke... VERY Weird...

My question is WHAT caused this? Could the flash do it. But that was 2 hours ago? [email protected]