Icicle Paranoia

It's always a little unsettling for me to walk or drive underneath an icicle. I always get that paranoid feeling that it's going to break off and come down on my skull or even worse, that I'm going to look up at that last second before it hits my head as it jams into my eye cavity. Something tells me that would hurt quite a bit.
I have always heard than an icicle would be a perfect murder weapon. The reason behind this theory is that the murder weapon would melt away and leave no evidence behind. But something tells me that Grissom (from CSI) would still find out who committed the murder. So maybe it isn't the perfect murder weapon after all?