WHILE ASCENDING A RAMP THE TRUCK STARTED SLIDING TOWARD THE WALL. THE FRONT TIRES BEGAN TO LIFT OFF THE GROUND. THE DRIVER LET OFF THE GAS & LET THE TRUCK ROLL BACK. THE TRUCK FRONT CAME DOWN BUT LIFTED AGAIN AT A 90% ANGLE, CAUSING PART OF THE LOAD TO SPILL. THE FRONT OF THE TRUCK CAME BACK DOWN RELATIVELY HARD. THE DRIVER, ALTHOUGH SEAT-BELTED, SUSTAINED A LACERATION & BRUISE.