The Hōlei sea arch, a famed landmark on Hawaii's remote southern coastline, has collapsed into the Pacific Ocean, the National Park Service (NPS) confirmed on Friday. The collapse followed a stretch of rough storms in the region in recent weeks.
The arch, about 90ft high, stood for over half a millennium in Hawaii Volcanoes National Park on the Big Island. It was naturally formed around 550 years ago through differential erosion by ocean waves.
Collapse timing and confirmation
The exact timing of the collapse is unknown. The NPS said the arch was still standing on Wednesday 23 September, when the park was temporarily closed during Tropical Storm Nolo, but had collapsed by Sunday night, 27 September.
In a 2014 description, the US Geological Survey said: "The arch formed in ancient lava flows by removing rock along cracks and weaker rocks. It will not be here for ever. Every day the ocean crashes against the pillar of the arch, eroding it a little more. One day, it will be gone."
Years of instability
The cliffs on either side of the sea arch had shown signs of instability for years, amid tropical systems and volcanic activity, according to the NPS, meaning the collapse had long been expected.
Earthquakes during the 2018 Kīlauea volcanic eruption and summit collapse damaged the cliffs around the arch. In January 2020, new cracks and instability prompted the park to close the original viewing area and open a safer one further from the cliff edge three months later. Later that year, huge surf from Tropical Storm Darby broke off a chunk of rock from the arch's lower portion.
Storm activity and impact
The Hawaiian islands have seen an unusually high number of severe storms this year, with storm activity in the Pacific running above average during the peak of hurricane season. The pattern is consistent with El Niño years, when the Pacific often sees more tropical storms and hurricanes.
Nolo, which rapidly intensified into a hurricane on 24 September – causing Volcanoes National Park to shutter – was the third major storm to devastate the islands in recent months. Residents were still recovering from hurricanes Lala in August and Lowell in early September, which had flooded homes and roads, toppled trees and caused power outages, when Nolo battered the islands with heavy rain and high surf.
Forecasters have warned there is a high probability that this "supercharged" El Niño will reach historic intensity, with its effects in strengthening storms compounded by the broader overheating of the planet caused by the burning of fossil fuels.
