A flexible harvesting header (40) having multiple sections supported by support arms (74), with the height of each arm being adjustable in response to a changing load. Load sensors (504) at first ends of the arms sense loads and generate electronic load signals. Hydraulic cylinders (80) at second ends of the arms are actuatable to raise and lower the first ends. A controller receives the load signals, determines whether actuating one or more of the hydraulic cylinders (80) is warranted due to a changing load, and if so, changes a hydraulic pressure to raise or lower the first ends to offset the changing load. Actuation may be warranted if the changing load exceeds a predetermined value. Further, the entire flexible cutter bar (68) may be raiseable in response to an electronic raise signal, and the controller may actuate all of the hydraulic cylinders (80) to raise the front ends of all of the support arms (74).
