Hōlei Sea Arch before and after its collapse into the Pacific Ocean in September 2026. USGS via AP.
A landmark that had stood on Hawaii’s rugged southern coastline for roughly 550 years is gone.
The Hōlei Sea Arch, a striking 90-foot volcanic rock formation in Hawaiʻi Volcanoes National Park, collapsed into the Pacific Ocean sometime between September 23 and September 27, 2026.
The National Park Service confirmed the collapse on October 1.
For visitors who had photographed the arch over the years, the change is dramatic. But from a geological perspective, the collapse is not really a surprise. It is the latest stage in a process that began when waves started attacking the volcanic rock.
What happened to the Hōlei Sea Arch?
The Hōlei Sea Arch was still standing on September 23. By Sunday night, September 27, it had collapsed.
Officials do not know the exact moment it happened.
The collapse may have occurred while Hawaiʻi Volcanoes National Park was temporarily closed during Tropical Storm Nolo, which brought powerful winds and heavy rain to the region. Nolo reached winds of up to 155 mph as it affected Hawaii.
The important point, however, is that the storm should not automatically be described as the sole cause.
The coastline had been unstable for years.
Why did the sea arch collapse?
The simple answer is erosion and structural weakening.
Hōlei was carved into an ancient lava flow through a process known as differential erosion. Some parts of the volcanic rock were harder than others. Waves repeatedly attacked the weaker sections, gradually creating openings in the cliff.
Over time, those openings can develop into caves and eventually into sea arches.
But erosion does not stop after an arch forms.
The waves continue attacking the remaining rock bridge until it eventually becomes too weak to support itself.
Video: “Iconic Hōlei Sea Arch in Hawaii collapses — see before and after.” Courtesy of USA TODAY, October 2, 2026.
The National Park Service describes sea arches as temporary features of Hawaii’s constantly changing coastline. Once the arch collapses, the remaining rock can eventually become a sea stack before further erosion reduces it even more.
The before-and-after images tell the story
Hōlei Sea Arch before and after its collapse into the Pacific Ocean. The comparison shows how dramatically Hawaii’s volcanic coastline can change over time. USGS via AP.
The image from before the collapse shows the familiar arch projecting from the cliff.
The second image shows the same coastline after the formation disappeared.
For readers, that comparison is more powerful than simply reading that a 90-foot landmark has collapsed.
Why was a 550-year-old landmark considered temporary?
This is perhaps the most interesting part of the story.
A human lifetime is short compared with geological time.
A formation that survived for approximately 550 years can appear permanent to generations of visitors. But geologically, it is only a moment.
The Hōlei Sea Arch was already undergoing the process that would eventually destroy it. The National Park Service had previously warned that the formation was beautiful but temporary and had a limited lifespan.
The coastline itself is continually changing.
Volcanic activity builds Hawaii. Wind, rain and ocean waves wear it down. These opposing forces have shaped the islands for millions of years.
The collapse of Hōlei is therefore not an isolated event. It is one visible moment in a much larger geological process.
The warning signs were already there
The arch did not disappear from a completely stable coastline.
The National Park Service says earthquakes associated with the 2018 Kīlauea eruption and summit collapse damaged cliffs near the arch.
In January 2020, new cracks and instability led officials to close the original viewing area. A safer viewing area farther from the cliff edge opened later that year.
Even before the final collapse, the formation had shown signs of deterioration.
That history is important because it explains why officials are now particularly concerned about people approaching the site.
What happens next?
The biggest immediate issue is visitor safety.
The collapse does not mean the area has suddenly become safe to explore.
Quite the opposite.
The National Park Service has warned visitors to stay away from the closed area and unstable coastal cliffs. Falling rocks and collapsing sections of coastline can create serious risks, while the rough Pacific below creates an additional drowning hazard
The coastline will also continue to evolve.
Other sections of cliff will erode. New cracks may develop. Eventually, other openings and arches could form as the same natural forces continue working on the volcanic rock.
In other words, the disappearance of Hōlei does not mean the end of the geological story.
It means the next chapter has begun.
Ravi Tiku’s Perspective
The real lesson from the Hōlei collapse is not simply that a beautiful tourist attraction has disappeared.
It is that nature does not preserve landmarks for our convenience.
We tend to think of mountains, cliffs and rock formations as permanent because their changes are usually too slow for us to notice. Hōlei reminds us that even a structure that survives for centuries can reach a final moment very quickly.
There is also a practical lesson for visitors.
A famous photograph can create the impression that a place is stable and safe. The reality can be very different. The same forces that created a spectacular landscape can also make it dangerous.
The National Park Service had already moved the viewing area away from the cliff because of instability. Now the collapse provides a dramatic reminder of why those warnings mattered.
Key Takeaway
The collapse of Hawaii’s Hōlei Sea Arch is not just the loss of a 550-year-old natural landmark.
It is a visible demonstration of how volcanic landscapes continue to change.
The arch was created by geological forces and eventually destroyed by the same broader forces of erosion that shaped it.
What looks permanent to us may be temporary in nature.
And sometimes, a photograph taken before the change becomes the record of a landmark that no longer exists.
#Hawaii #HoleiSeaArch #HawaiiVolcanoes #NaturalLandmarks #Geology
Source context: National Park Service; CBS News/AP. The NPS confirms the arch’s collapse and provides the geological and safety context.