At the end of the austral winter, the Southern Ocean sea ice covers over 20 million square kilometers of ocean, an area larger than Antarctica. In November the ice begins to melt rapidly, retreating to only 20% of winter value by February. The basis of our understanding of the complex Southern Ocean is data obtained during the ice‐free period; yet, it is in the ice‐covered state, where the data base is essentially zero, that many significant events are believed to take place. Direct observations within the ice cover are limited to ships inadvertently locked in the ice, notably the Weddell Sea experience of the Deutschland in 1912, to coastal observations at Antarctic stations, and to a few year‐long bottom‐moored current meter deployments below the winter ice: in total, a very small data set that is restricted to a few types of measurements. It is likely that the extensive winter ice cover surrounding Antarctica represents the largest segment of the world ocean without a fundamental d