Toughest ice pack I can ever remember was one back in January 2008. I drove a Mack Granite tri-axle dump truck with a steel dump body back then. The thing weighed 28,000 lbs empty, and when I drove into the quarry where I was supposed to pick up a load, I rode on top of the unplowed ice pack. It was amazing. Needless to say, the quarry folks sent all the trucks back home that morning...