ABSTRACTThe robustness of a simple flow-line model has been tested against new data from Storglaciären. The model appears robust for given subglacial geometry. A realistic longitudinal profile and acceptable ice surface velocities were generated. The model has been tested in a series of sensitivity experiments, and was found to react strongly to changes in climatic parameters (ΔELA of 25 m,∼0.25 meters water equivalent). Due to the uneven subglacial topography underlying Storglaciären, its behavior is non-linear and prone to considerable hysteresis. From these experiments it appears that Storglaciären was not in balance with its climate when it reached its maximum historic extent in 1915.