The Hōlei Sea Arch, a natural landmark carved from a lava flow roughly 550 years old, has fallen into the Pacific Ocean off the Big Island. Waves gradually wore away the arch over centuries, leaving nothing standing along the coastline of Hawaiʻi Volcanoes National Park. The arch once reached about 90 feet in height.
The fall was anticipated for a long time, and it came to pass within days of the park service confirming the arch was still standing. On September 23, the National Park Service confirmed that Hōlei Sea Arch was still standing. By September 27, it had vanished entirely. Nobody knows exactly when the structure fell apart. The park was temporarily shut down during Tropical Storm Nolo, and officials said the collapse could have taken place while visitors were absent.
How the Arch Formed
The arch at Hōlei came into being due to differential erosion, which involved waves steadily stripping away softer rock while taking advantage of fissures within the old lava flow. Over a decade ago, the US Geological Survey cautioned that the Pacific was eating away at the arch daily, and that it would ultimately vanish.
For generations, the ocean’s waves carved a natural arch into the island’s cliffs, shaping it over time through erosion. Softer stone gave way beneath the constant pounding, while harder rock held firm, preserving the arch’s distinctive form that brought visitors to the Big Island. The process spanned centuries, and when the weakened structure finally reached its breaking point, the collapse came quickly.
Warning Signs Before the Fall
The arch’s state had also worsened more recently. During Kīlauea’s 2018 eruption and summit collapse, earthquakes damaged nearby cliffs, and further cracks and instability led the park to close the original viewing area in January 2020. Those occurrences weakened the ground around the arch and increased the likelihood of collapse.
An October 2 post on X from the US Department of the Interior confirmed that the Arch had fallen down. Officials noted that the exact moment of collapse is still unknown, even though they made the announcement after the arch had already disappeared. The park was closed during Tropical Storm Nolo, so no visitors were present when the structure finally collapsed.
What the Collapse Means for Visitors
Hawaii’s coastline keeps changing shape, and the forces that formed Hōlei are still at work today. The National Park Service says that sea arches don’t last. Waves keep wearing away rock bridges until they fall apart, and cliffs move farther inland over time.
After pictures emerged showing visitors entering the closed-off spot where Hōlei once stood, park authorities have issued warnings against approaching the location. The cliffs around the site are still unstable, capable of giving way without warning, and the park has cautioned that anyone who enters the area faces the risk of falling into the rough waters below.
“Anyone entering the area risks falling into the rough waters below.”
The message carries real weight: the cliffs that once held up the arch have been weakened, and the park has shut down the viewing area altogether, a move aimed at keeping visitors safe.
The Natural History of Coastal Erosion
Waves batter a headland, wearing away softer rock more quickly than harder rock, and over time that action forms a hollow space. Eventually, that space opens into a full arch. When the arch weakens, it gives way, leaving behind a stack or merely returning the rock to the sea.
The familiar sequence of an arch’s destruction explains Hōlei’s fall. It stood for centuries, weathered by the constant battering of the Pacific, until the sea found its weakest point. Once that point gave way, the arch collapsed, changing from a visible landmark into memory.
The Coastline Continues to Change
The very forces that gave birth to Hōlei keep altering the coast. Cliffs will keep pulling back, arches will appear and then vanish, and the land will shift as time passes. The National Park Service calls this natural, with each collapse simply ending one formation while starting another.
The message for visitors is simple: keep out of closed areas. Officials have shut down the original viewing spot, and they expect people to honor those limits. The cliffs are unstable, and going inside them puts anyone who enters at real risk.
The Loss of a Landmark
Nature’s power was on display when Hōlei Sea Arch collapsed, a landmark that endured for centuries before its final fall. It cannot be restored now, though the coastline keeps changing.
Hōlei’s collapse marks a significant loss for the Big Island’s natural legacy, yet it serves as a reminder of our limited control over nature. Preservation is fleeting at best, and the arch itself has now vanished. Still, the coastline continues to shift, and future generations will witness a new formation where the arch once stood.
Closing the area and warning visitors is the correct approach from the park service. The cliffs are unstable, which means going inside them endangers lives. The warning has been given plainly, and people should listen to it.
The Big Island has lost Hōlei Sea Arch, and its memory will vanish with time. The coastline will keep changing, and the next formation will come up from the very lava that created the arch. Until then, the arch is gone, and the island is a little more still.
Source material: “Hawaii’s 550-year-old Hōlei Sea Arch collapses into ocean,” Dexerto.
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