The 90-foot Hōlei Sea Arch has disappeared from Hawaiʻi Volcanoes National Park after centuries of wave-driven erosion, prompting officials to warn visitors that the surrounding volcanic cliffs remain unstable and can collapse without warning.
By yourNEWS Media Newsroom
One of Hawaiʻi Volcanoes National Park’s best-known coastal formations has collapsed into the Pacific Ocean, transforming a stretch of the Big Island shoreline that had drawn visitors to the end of Chain of Craters Road for years.
The National Park Service confirmed that the Hōlei Sea Arch, a roughly 90-foot-tall formation carved into ancient lava cliffs, was no longer standing after disappearing sometime between Sept. 23 and Sept. 27.
Park officials said the exact time of the collapse is unknown. The arch was still intact on Wednesday, Sept. 23, but had fallen by Sunday night, Sept. 27, a period during which most of the park was temporarily closed as Tropical Storm Nolo approached Hawaiʻi Island. The Park Service has not determined that the storm caused the collapse, saying only that it could have occurred during the closure.
The loss was not considered unexpected.
For years, the National Park Service had warned visitors that Hōlei was a temporary geological formation with a limited lifespan as relentless waves eroded the volcanic coastline.
Its disappearance marks “the latest transformation of the park’s remote and rugged coastline,” the agency said when announcing the collapse.
The arch extended from steep lava cliffs into the Pacific and stood approximately 90 feet, or 27.4 meters, high. It was reached from a viewing area near the coastal end of Chain of Craters Road.
The surrounding lava flow is approximately 550 years old. Over time, waves exploited differences in the hardness of individual lava layers, gradually carving through weaker rock in a process known as differential erosion until the opening developed into the familiar sea arch.
That same process continued weakening the formation after the arch took shape.
The surrounding cliffs had shown signs of instability for years. Earthquakes accompanying the 2018 Kīlauea eruption and summit collapse damaged sections of coastline near the arch. New cracks and unstable ground prompted the park to close its original viewing area in January 2020 and establish a safer observation point farther from the cliff edge.
Powerful surf later broke away additional rock from the lower portion of the arch, providing another visible indication that the structure was continuing to deteriorate.
The Park Service had consequently cautioned visitors well before the final collapse that Hōlei would eventually fall into the ocean as the coastline migrated inland.
Officials are now emphasizing that the disappearance of the arch does not mean the danger has ended.
The newly exposed coastal cliffs remain unstable, and the volcanic terrain can fracture or give way with little or no warning. The cliffs also drop nearly vertically into rough Pacific waters, creating a potentially deadly combination for anyone approaching the edge.
“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 National Park Service said.
Visitors are being instructed to stay out of closed areas and remain well back from cliff edges.
The warning has taken on added importance because people have continued approaching the former arch site despite the collapse and posted photographs from restricted areas online.
The National Park Service says the coastline can collapse without warning. The terrain also contains deep cracks, loose and uneven lava and sharp volcanic rock that can create hazards even away from an obvious cliff edge.
Hōlei had become one of the recognizable landmarks along the nearly 19-mile Chain of Craters Road, which descends from the Kīlauea summit area toward the coast.
Hawaiʻi Public Radio reported that visitors continued making the drive after the arch disappeared, with some learning only after arriving that the landmark was gone. The surrounding cliffs and coastal scenery remain accessible from designated areas even though the arch itself has vanished.
The formation’s name also reflects the native environment surrounding Hawaiʻi’s volcanic landscape.
According to the National Park Service, Hōlei is the name of a small endemic Hawaiian plant in the milkweed family, Ochrosia.
Although the loss of a prominent landmark prompted disappointment from previous visitors, the Park Service has long described sea arches as temporary features rather than permanent fixtures.
Ocean waves continually attack the base of Hawaiʻi Island’s coastal cliffs, removing weaker material while leaving harder rock behind. Openings can become caves, caves can enlarge into arches, and eventually the remaining rock can no longer support itself.
When an arch collapses, continued erosion reshapes the cliff again, and new formations can eventually emerge elsewhere along the coastline.
Hōlei therefore disappeared through the same geological forces that originally created it.
The Park Service had previously explained that while the arch would eventually “crumble into the sea,” other formations could replace it as the cliff slowly shifts inland.
The process unfolded sometime during four days in late September.
When visitors last saw Hōlei standing on Sept. 23, it remained a 90-foot gateway of black volcanic rock above the Pacific. By Sept. 27, the opening and much of the formation had fallen into the ocean, leaving a newly altered cliff where one of Hawaiʻi Volcanoes National Park’s most distinctive coastal landmarks had stood.
Original article
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