Earthshots: Satellite Images of Environmental Change

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» Cape Cod, Massachusetts, USA

Along some coastlines, long, narrow islands stand guard. These barrier islands are attractive to tourists, but they also protect the mainland coast from storm surge and are important beach, dune, and marsh habitats. Those islands do take a beating though.

These images focus on the southeastern elbow of Cape Cod, Massachusetts. Wave action, currents, winds, and tides are constantly changing the barrier islands here. Strong storms can change them quite suddenly.

In 1984, a nearly unbroken barrier island lines the Massachusetts coast at Chatham. To the south, Monomoy Island extends into the ocean like a teardrop. The other subsections of this Earthshots page show over 35 years of changes to these barrier islands as seen by three different Landsat satellites.

Map of the featured area.

Ocean currents, and the sediments they transport, have constantly shifted the Cape Cod barrier islands over time. Some of the abrupt changes, however, can be linked directly to a storm.

For example, a nor’easter in January 1987 cut a new inlet through North Beach and formed South Beach Island. South Beach connected to the mainland by 1993. Throughout the rest of the 1990s and early 2000s, South Beach reached southward toward South Monomoy and eventually connected to it.

In 2007, a nor’easter cut another new inlet through North Beach. This storm also wiped out several beach houses. Another abrupt change happened in February 2013 when a storm cut a new inlet through South Beach.

All of these changes can be seen in the Landsat image that corresponds to the year in which the storm occurred.

Monomoy is the southernmost barrier island in this system. It once consisted of North Monomoy Island and South Monomoy Island. Storms, high winds, tide, and surf endlessly change the island. The Landsat imagery shows South Beach Island migrating southward to join Monomoy, which is now considered one island. All of Monomoy Island (North and South) are designated as Monomoy National Wildlife Refuge.

In the years since European settlers began making coastline maps, the changes to all of these islands and beaches have been observed in fairly predictable patterns. The dilemma now, with an increasing population, is to monitor how storms, flooding, and shoreline erosion affect property and both human and wildlife populations.

Play this animation to see the change in this area from 1984 to 2018.


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