I guess the sand stabilized it. There isn´t much you could do now. I would not take the risk...
Glass is stable as long it has its structural stability. Such cracks disturb the stability and provoke other cracks. In worst case you just hear a loud boom and get your personal tsunami.
Glass is stable as long it has its structural stability. Such cracks disturb the stability and provoke other cracks. In worst case you just hear a loud boom and get your personal tsunami.