Thermally activated domain-wall depinning in permalloy nanowires is studied at temperatures of liquid helium and above by means of time series at constant bias fields as well as by hysteresis measurements of Hall voltages recorded by Hall micromagnetometry. Domain walls are pinned at triangular notches in nanowires and detected noninvasively by micron-sized Hall sensors underneath. The magnitudes of the Hall voltages correspond to the mean perpendicular components of the stray fields of the domain walls pinned at the notches. From the time evolution as well as the field evolution of the Hall voltages, thermally activated processes are identified that precede the depinning event and characterize individual depinning paths. (C) 2013 AIP Publishing LLC.