The High Temperature this day was in the upper 80s F. I use a sun shade in my car. I drove home and the temperature in the garage was never above 90 F degrees. At 9pm, I went into the garage and heard a crackling sound. I thought it was a rodent chewing on something. I walked towards my Outback and noted the sound was at the car. Then, I noticed the sunroof appeared to have exploded upward. There was not glass on the ground anywhere around the car. I had not been hit by any rocks or debris at anytime. The dealer so far has said they have never seen this before and not sure if the manufacture or extended Warranty is going to cover this. They are saying prepare for an insurance claim. I could still here the cracking of the glass as I walked up to video it.