Persistent, moderate to strong southerly surface winds, so-called barrier winds, develop along the east side of the Antarctic Peninsula when the prevailing easterlies over the central and southern Weddell Sea carry cold, stable air masses toward the 1200- to 2000-m-high mountain barrier. Because of the lack of observations from the Weddell Sea itself, wind data for the topographically similar Ross Ice Shelf area are used to estimate the probable lateral extent of barrier winds. Frequency and duration of different types of winds at the key station Matienzo (65¿S, 60¿W) indicate the importance of the barrier effect for the drift of large ice masses northward and northeastward to the relatively low latitude of 63¿S. Such a guided discharge of ice into the belt of the subpolar and mid-latitude westerlies, not to be found in other sectors of the Antarctic, has a profound effect on the temperature conditions over the southern South Atlantic. Evidence for each of these statements is presented.