The STARE radar system has for the first time been used to study Pi 2 pulsations associated with substorm onsets. Such pulsations have a period which typically makes them only marginally observable with STARE; nevertheless, an event has been identified. The spatial and temporal variations of the observed ionospheric flow vectors, and consequently also the electric field vectors, are complex and require further study, but are qualitatively comparable to model predictions. Magnetic field oscillations computed from the STARE data using the Biot-Savart law correlate well with magnetometer data. ¿ American Geophysical Union 1990