During storm conditions, which coastal feature forms seaward as sand is moved?

• A. Longshore bars
• B. Dune fields
• C. Lagoons
• D. Barrier flats

Answer: (A)

Storms boost wave energy and currents that move sand along the coast and offshore. As sediment is scoured from the beach and carried seaward by these forces, it tends to accumulate in elongated ridges just offshore. These offshore ridges run parallel to the coastline and are formed by the offshore sediment transport amplified by storm conditions—this is what longshore bars are. They act as a barrier between the open sea and the inner shore, shaping how waves break and how the beach responds to erosion and accretion.

Dune fields sit on land and are built by wind depositing sand above the high-tide line, not by offshore transport. Lagoons are shallow water bodies behind barrier systems, separated from the sea by the barrier itself. Barrier flats are low-lying areas landward of the barrier that form over longer timescales and from different processes. The seaward formation of a longshore bar during storms is the strongest match to the described process.