A crane includes a carrier unit having a chassis, tires connected to the chassis, a carrier deck and outriggers. A superstructure is mounted on the carrier unit, the superstructure includes a telescoping boom. A slope sensor is operably connected to the carrier unit and configured to detect a pitch and/or a roll of the carrier unit during a lift operation. The crane further includes a system for monitoring a load lifted by the telescoping boom. The system is configured to determine the current load lifted by the telescoping boom, receive pitch and/or roll information of the carrier unit from the slope sensor, adjust coordinates of the crane in a coordinate system based on the pitch and/or roll information, determine a transformed operating radius using the adjusted coordinates; and compare the load lifted to a rated capacity at the transformed operating radius.