We have Pella double pane windows - the interior pane is removable.

A few nights ago (around 2am), the interior pane in a guest bedroom suddenly exploded/broke into a million pieces. No one was in the room and the entire house was empty. In fact, no one had been in that guestroom for weeks. The exterior pane is fine, no damage whatsover.

What would cause a window to suddently break like that? It was nearly 3 years old. Any ideas? Could this happen on othjer windows? We only learned about it from the alarm company glass break sensor going off.