"All of the sudden, the dune started building out," said Barrett.
And over the past few years, more homes have crept out onto that dune.
As you drive onto Plum Island, near the popular parking lot next to the seaside restaurant Jeannie's, there's a string of old cottages. Among them, a few hundred yards to the south of the parking lot, sat a simple building that literally tumbled its way into becoming the symbol of Plum Island's losing battle with the sea.
It was called the Salt Box. Exactly 32 years ago, despite its owners' best efforts to save it, it fell over the eroding cliff. It wasn't the first nor the last to fall into the sea, but dramatic pictures of it lying on its side were widely circulated. Some people still have it hanging on their walls.
It was hauled back up, and the dune where it stood has grown out several feet toward the sea. But it's starting to erode again, just as it did in the mid-'70s.
Earlier this month, Plum Islanders gathered for a meeting to discuss the latest erosion crisis facing the Center. In the audience was Byron Matthews, the former Newburyport mayor who 35 years ago waged the same war against the sea, trying to save the Center.
"It was the same situation you have today. It's like deja-vu," he said in an interview after the meeting. "It's never going to cease."
Plum Island, like every sandy shoreline, is a constantly changing land mass — eroding in some places, growing in others, always at the mercy of tides, current, and weather.
The changes have been going on for millennia. But if the past is any indication, changes are almost always unpredictable, quick, and catastrophic.