Garage Opener Help

[HEEP]

Alright guys,
So last night after I went to bed, all of a sudden my wife wakes me up and says the garage door had gone up. Jumped up, and went down to the garage to see that one side was all the way up. Looked around and nothing looked bad or out of place. Closed the door, turned the alarm on, and went back to bed. 3 minutes later, alarm went off. Up again, grabbed the gun, and told the wife to tell the alarm company to send sheriff out. Waited, in the hall for a few minute, and then made my way down to the alarm pad in the basement that tells me what door disconnected. It was the back door or garage door again. Went into the garage and noticed the other door had come up enough the first time to break the contact. Didn't see that so that is why the alarm went off.
So, I closed it, and cancelled the sheriff and sent all back to bed. But, I have no idea why the garage door went up in the first place. I only have 1 transmitter that works on that door, because I rarely use it. But with both doors going up at the same time is really odd. Anyone have any ideas what would cause this? Im baffled.