Well I would say it's not too common, at least from my years of off roading here in Florida. This was a first for me. Once we got the truck out I went back and checked that hole. I looks like there was a network of Pine roots and water from Hurricane Sally boiled the dirt out from under them. Just enough to support the front end but broke through when the weight of the rear came down. You can see some of those roots in one of the rear photos my wife took. I was the lead truck, so it's my dumb azz for not walking the holes before entering. Just got caught being lazy. Yea, I'm a huge fan of dipping the truck, wished I had dipped it again. Hunting season will kick off here in November. Certainly I will dip it soon.
