On Cape Cod, the latest barrage of wind and waves, exacerbated by climate change, turns concern to desperation

A home in Truro was supported by pilings due to the erosion of the dune it was built on Monday.David L. Ryan/Globe Staff

The howling winds and heavy surf became so intense that Betsy Pottey and her husband had to abandon the beach house where she has lived since she was born.

With waves slamming into the windows of their coastal home in Sandwich, the Potteys worried that they might lose the place altogether. In the end, the three-bedroom house remained standing, but much of the bluff protecting it had disappeared.

“We could feel the house swaying,” said Pottey, 69, who was trying to celebrate her birthday as the storm ripped through Cape Cod on Saturday with punishing winds and heavy snow.

With seas rising and storms intensifying as a result of climate change, she worried about how long the house would survive. ”It’s such a beautiful spot,” she said. “We really hope we don’t have to leave.”

The weekend’s bomb cyclone brought record-matching snowfall to Boston, sparked power outages for more than 100,000 people across the state, and forced commerce, roads, and school districts to shut down. It also swept away parts of the shoreline, serving as a clear reminder of the vulnerability facing many coastal parts of Massachusetts.

Sandwich wasn’t the only coastal town battered by the storm. Fierce winds and a powerful storm surge nearly toppled a historic beach house in Truro. The former US Coast Guard building, which has survived many other storms since it was built on Ballston Beach in 1850, was left teetering on stilts on Saturday. Its pilings cracked as gusts of 99 mile-per-hour winds ravaged the coast and parts of the home’s foundation slipped into the sea.

Coastal erosion has long shaped Cape Cod and much of the state’s coast. But as global warming fuels more powerful storms — bringing heavier precipitation, higher tides, and more intense winds and waves — erosion is likely to accelerate, claiming more of the coast and taking any structures with it into the sea.

In 2018, scientists at the Center for Coastal Studies in Provincetown found that along Massachusetts’ 1,500 miles of shoreline, some 65 acres are swallowed by the sea each year.

It’s “very likely that the impacts have worsened” since then,” said Mark Borrelli, a coastal geologist at the center.

Cape Cod is particularly vulnerable to coastal erosion, as the soft, loosely packed sand left over from the last Ice Age is easily disturbed, especially as coastal waters warm at an accelerating rate and sea levels continue to rise.

“Those warm waters feed storms,” said Jack Clarke, an environmental advocate and former member of the state’s Coastal Erosion Commission, said. “They put a lot of moisture into storms . . . and those big storms create very, very large waves that erode the shoreline.”

In recent years, some communities have sought to prevent erosion by allowing residents to build seawalls or otherwise fortify their bluffs. But Clarke notes how those measures can be destructive to the environment and create erosion problems elsewhere.

“The seawall interrupts the natural flow of sand,” Clarke said. “That interruption of nature’s forces has repercussions that are not good if you’re trying to protect manmade structures.”

Clarke said some communities may soon need to consider a “managed retreat” of residents who live along the coast.

“The need for climate change adaptation in this retreat from the shoreline takes planning,” he said. “The actual implementation of plans to retreat should happen before the crisis.”

The coastal erosion and flooding from the weekend storm could have been far worse, especially on Nantucket, where sea levels rose 3 feet higher than the typical high tide, said Christopher Piecuch, an oceanographer at the Woods Hole Oceanographic Institution.

If the strongest gusts and the lowest barometric pressures arrived six hours earlier, the sea levels could have been a foot higher. High winds increase wave action, while the lower pressures, with less weight from the atmosphere, allow seas to rise higher.

“What happened wasn’t a worst case scenario,” he said. “An additional foot would have meant substantially more flooding.”

In Sandwich, where the town’s historic boardwalk suffered severe damage during the storm, many residents were still assessing the damage on Monday.

Irene Davis, who has spent years urging the town and federal officials to do more to protect Sandwich, felt a sense of despair about the impact of the storm.

“I grew up in those dunes and jumping off that boardwalk,” she said. “Back in 2015, I was asked by a Boston reporter what I worried the most about. I told them that I worried about the day when someone would ask me what happened to our dunes and to our beloved boardwalk, and why didn’t anyone do something to stop it. That day has sadly come.”

Susan Lott’s cottage on Spring Hill Beach has survived many storms since her family bought the coastal property in the 1930s, but few landed with as much force as last weekend’s bomb cyclone.

”We got hammered,” said Lott, 77, who hopes to hold on to their cottage for her grandchildren.

So much sand that protected her home had been ripped away by the sea that she expected her family and many of their neighbors would each have to spend tens of thousands of dollars to bring in more sand. Without such a buffer, their homes are unlikely to survive another major storm, she said.

”The nor’easters are becoming increasingly relentless,” she said. “Climate change is certainly playing a role, but we’ll keep doing what we can to protect the cottage.”

“Sea levels . . . have risen nearly a foot in the last 100 years in most parts of the Northeast,” said Erika Lentz, a research geologist at the Coastal and Marine Science Center of the United States Geological Survey in Woods Hole. “That amount is likely to double or even quadruple in the next 80 years, and those are not even the worst case scenarios.”