Why did Hawaii's iconic Hōlei Sea Arch collapse into the Pacific after 500 years? Before-and-after photos show the change

The iconic Hōlei Sea Arch in Hawaiʻi Volcanoes National Park has collapsed into the Pacific Ocean, more than 500 years after it was naturally formed, according to the National Park Service.

The iconic Hōlei Sea Arch in Hawaiʻi Volcanoes National Park has collapsed. (Facebook/ Hawai'i Volcanoes National Park)Where was it located?The Hōlei Sea Arch stood about 90 feet (27 meters) tall along the southern coast of Hawaiʻi’s Big Island, within Hawaiʻi Volcanoes National Park.

The arch was still standing on September 23 but had collapsed by the night of September 27. The exact time is unknown, but the collapse may have occurred while the park was temporarily closed during Tropical Storm Nolo, the National Park Service said.

The collapse was the result of natural erosion that had been gradually weakening the rock for centuries.

Powerful waves repeatedly battered the cliff, wearing away softer sections of rock faster than the harder layers. Over time, this process—known as differential erosion—left the arch increasingly fragile.

The National Park Service had long warned that the formation would eventually collapse into the ocean. While its exact lifespan could not be predicted, its eventual disappearance was considered a natural part of the coastline’s evolution.

“The sea arch will eventually crumble into the sea,” the NPS said in its description of the site, noting that new formations would eventually emerge as erosion continues to move the cliff inland.

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The National Park Service is urging visitors to stay away from the area around the former arch and other unstable coastal cliffs.

"Please, stay back from the unstable coastal cliff edges which drop off vertically into the ocean and present a serious falling hazard. Photos on social media show people entering the closed area near where the sea arch once stood, putting themselves and first responders at great risk of falling and drowning off the rough, wave-swept coast," the agency warned.

Vaishnavi Vaidyanathan leads the US Desk at Hindustan Times, where she writes, strategises coverage, and ensures quality across all beats. With eight years of experience covering US news for leading publications, she has reported extensively on politics, entertainment, and sports. Vaishnavi holds a graduate degree in English, Journalism, and Psychology, and completed her PG Diploma in Broadcast Journalism from the Manorama School of Communication, where she was awarded the prestigious Mammen Mappillai Award for Best Outgoing Student. She began her career at the International Business Times (US Edition), covering US breaking news, politics, and entertainment. She later joined Opoyi, reporting across all beats, including US sports and trending stories. Prior to Hindustan Times, she served as World Lead at Times Now News, covering comprehensive world news and events. Vaishnavi has expertise in politics, entertainment, and breaking news, and enjoys tackling stories across a wide range of topics. Beyond the newsroom, she is an avid traveller, a foodie who loves exploring new restaurants, and a pop culture enthusiast who enjoys watching latest shows and films. She also enjoys engaging in debates and discussions on Reddit.Read More