Years ago I had a car with a stone chip in the windshield on the passenger side. On the way to work one frigid morning, as the car was warming up I happened to spot the chip developing a crack that was starting to creep across the glass towards my side - looked just like a snake making its way. I could see that it was going to pass through the area that I looked through, so I stopped and rubbed the glass on the inside hard with my hand towards the top of the glass. Sure enough, when the crack reached the area I had rubbed, it turned and went up to the top of the glass.