What does the term Undertow describe in marine conditions?

• A. An underwater current that moves in the opposite direction to what is expected.
• B. A surface current that pulls water toward shore.
• C. An ocean floor current that moves laterally.
• D. A wave pattern caused by wind flow.

Answer: (A)

Undertow is the water returning seaward beneath the surface after waves break on the shore. As waves crash and water runs up the beach, gravity pulls some of that water back toward deeper water, creating a bottom-directed flow that moves away from the shore. It can be felt as a pull at the feet even if the surface water looks to be moving toward the beach, and it’s typically a subsurface, broad return flow rather than a strong surface jet. This differs from rip currents, which are fast, narrow surface currents that pull directly offshore. The other choices describe onshore surface flow, a bottom-side lateral current, or a wind-driven wave pattern, none of which define the return flow under the shore.