My boots fell apart while on the roof...

I've been doing this for quite some time now and I'm a fairly confident climber. Well, today I was running up the front slope of a roof I was inspecting and felt like my Velcro pads were a little loose. I looked down to see the sock I was wearing poking through the bottom of my Cougar Paws as they fell apart. I'm glad I was right at the ridge because about the same time I realized what was happening, I started to slip, so I went stomach-first onto this roof, grabbing on for dear life as I almost fall 2 story's and die. It's hard to trust your equipment when it fails so catastrophically. Never seen anything like this or heard anyone else talk about it.