Some flow phenomena observed in the coastal ocean are clearly unrelated to the wind. One of the most spectacular is the apparently spontaneous reversal of a well-established coastal current set up previously by wind. Such reversals have been documented in detail in Lake Ontario, but they have also been noted in other locations. Current reversals, and other less drastic changes in the flow, are often found to propagate alongshore in one specific direction only, leaving the coast to the right. Thus in the Great Lakes, such ‘signals’ propagate cyclonically, or counterclockwise, around a basin, along the east coast of North America south westward, along the west coast northward. For brevity, this direction will be called ‘cyclonic’ in all applications.