Abstract: A D8 Caterpillar was being used by a tower logging crew as a portable tailhold for different roads. The Caterpillar had to be moved down the hill, on an approximately 60 degree slope, for the next road. The ground was soft from previous hard rains. Employee #1, a hook tender, started down over the hill until the Caterpillar hung up on a snag. The employee sawed off the snag. He then tried to maneuver the Caterpillar, now free of the snag, around its stump. The Caterpillar, once sideways, started sliding down the hill in the soft dirt. After sliding approximately 6 ft, the Caterpillar dug down to solid rock and then started rolling over, downhill. The Caterpillar rolled over four times. Employee #1 was thrown out on its third roll. His lower legs were seriously injured. The right leg was later amputated at the hospital.