Expendable bathythermography, wind, and sea surface temperature data collected along 12 crossings of the Drake Passage were analyzed to describe variations in the structure of the antarctic polar frontal zone within a single austral summer (1976--1977). Collected from icebreakers, research and supply vessels traveling to and from the Antarctic, these data show the development of cold features within the antarctic polar frontal zone, which are most likely expressions of eddies or meanders formed at the polar front. These cold features appear to widen the antarctic polar frontal zone by intensifying the subantarctic front and moving it to the north. The majority of the temperature sections contain such cold features, whose signature can be identified as an inflection in average profiles of 450-m heat content and sea surface temperature. Changes in air temperature and wind direction over the antarctic polar frontal zone observed when cold features are present may reflect the influence of the ocean on the overlying atmosphere.