Sudden-commencement-associated geomagnetic pulsations have been studied using the magnetometer records from Mirny (&PHgr;'=-77.2¿) and Heiss Island (&PHgr;'=74.1¿) high-latitude observatories, where &PHgr;' is the corrected geomagnetic latitude. These pulsations have time delays from the onsets ranging between 4 and 22 min. Dominant periods of the pulsations observed lie in the range 20--50 s. The pulsations were accompanied by absorption events that are quite different from sudden commencement absorption and auroral absorption events observed earlier at high latitudes. The results of multifactoral analysis demonstrated that the solar wind speed is the most important parameter controlling the geomagnetic pulsation occurrence. It was assumed that a Kelvin-Helmholtz instability arising at some magnetospheric boundaries seems to be a more probable cause of the pulsations observed. The work gives further evidence to the results of Rostoker et al. [1984>, and Connors and Rostoker [1993>, who considered auroral and magnetic disturbances in the light of KHI development at some magnetospheric interfaces. ¿ American Geophysical Union 1996