Beneath the Dune Grass

After September’s nor’easter, Ocean City’s dunes offered a rare look at the living system beneath the sand.

For most of the year, the dune grass in Ocean City sits just outside the picture. We pass it on the way through, with beach chairs in hand and our eyes already on the ocean. It separates the sand from the condos, the streets and the rest of town. After September’s nor’easter, parts of that familiar edge looked entirely different. The storm cut a steep shelf into the dunes, leaving American beachgrass at the top and long, tangled strands hanging down the exposed sand.

Dune scarp in Ocean City, Maryland after a strong September 2026 nor'easter.

These photographs reveal what is usually hidden. The visible grass is only one part of the plant. Below the surface, roots absorb water and anchor the plant in loose sand. Underground stems called rhizomes spread outward and produce new shoots. American beachgrass grows both horizontal and vertical rhizomes, extending through the dune as it develops. The exposed strands give us a sense of that network.

The steep edge is called a dune scarp. It forms when high water and waves reach the dune and pull sand from its ocean-facing side. It can appear after a single storm, even though the dune took years to build. Some of the sand swept away may collect offshore and return to the beach during calmer conditions. Replacing the sand lost from the dune is a slower process.

Beachgrass helps that process along in an unusually practical way. Wind pushes dry sand inland across the open beach. The grass slows the wind near the ground, allowing some of that sand to settle around its stems. As the sand accumulates and buries the plant, American beachgrass can send new growth upward. Its rhizomes spread into the new sand, and the growing network helps hold it in place. That is why the strands in the photographs are so long and numerous: the plant has been growing through a dune that built around it over time.

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Ocean City’s dunes also have a town history. The barrier island had natural dunes long before there was a resort here, but much of the continuous dune line along today’s developed beachfront was built through a public storm protection project. In a phase completed in 1992, millions of cubic yards of sand were placed to widen the beach and create a dune from 27th Street to 146th Street. The project also built a steel and concrete seawall along the boardwalk area farther south. Completed in 1994, it has required continued beach replenishment, dune planting, fencing and maintenance ever since.

Sand is pumped onto the beach at Ocean City in 1991 as part of initial construction of the beach berm and dune that are parts of the existing coastal storm risk management project. The Corps of Engineers, working closely with the state of Maryland and Ocean City, has continued to maintain the project over the years, and it has prevented an estimated nearly $1 billion in damages since initial construction.

The grass we walk past is part of a shoreline that Ocean City has spent decades building and caring for. That work connects the tides to the town. A wide beach gives waves room to break before they reach the dune. The dune adds height and a reserve of sand between the ocean and what stands behind it. Beachgrass helps catch windblown sand and stabilize the dune as it grows, though no grass can stop powerful surf from cutting into it. An eroded dune can still have helped protect the land behind it during a storm. The loss matters, too: with less sand in place, there is less of a buffer for the next one.

Ocean City will settle back into its familiar rhythms. The beach will change shape again, as it always does, and the exposed edge will be inspected and, over time, repaired or rebuilt. But for now the scarp makes one part of our shoreline unusually plain to see.

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1. National Park Service, “American Beach Grass”: https://home.nps.gov/gate/learn/nature/american-beach-grass.htm

2. U.S. Geological Survey, “Storm-Induced Coastal Change”: https://www.usgs.gov/centers/spcmsc/science/storm-induced-coastal-change

3. USDA Natural Resources Conservation Service, “A Guide to Conservation Plantings on Critical Areas for the Northeast”: https://www.nrcs.usda.gov/plantmaterials/nypmspu11417.pdf

4. Town of Ocean City, “Dune Crossovers” and “Beach Replenishment”: https://oceancitymd.gov/oc/departments/engineering/dune-crossings/ ; https://oceancitymd.gov/oc/departments/engineering/beach-replenishment/

5. NOAA Climate Prediction Center, “ENSO Diagnostic Discussion,” September 10, 2026: https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml