It's that time of the year here as well. As the frosts come, we regularly hear loud cracks and splashes just prior to dawn, 2am if really cold. Water in fissures of the rock bars freezes, expands, and bang! Some fragments are considerable and leg-breakers.....quite spectacular, and at first we didn't know what the score was.
Could this be further evidence of water on Mars?
The Mos Eisley cantina entrance maybe?