PORTLAND, Ore. (KOIN) – A second sinkhole, much deeper than the first, has been discovered at Cape Kiwanda State Natural Area. 

This second sinkhole, which was found Monday, closely resembles the one that was discovered at the park in January. However, its gaping maw is about half the size. 

Sinkhole number one was found in January and at the time, Oregon State Parks Park Manager Jason Elkins told KOIN 6 News that it measured about 20 feet wide and 15 feet deep. It is now estimated to be 25 feet across. 

The second sinkhole formed about 10 inches away from the first and Stefanie Knowlton, public information officer for Oregon Parks and Recreation Department, said it measures about 10 feet across and 30 feet deep. 

  • A second sinkhole was discovered in Cape Kiwanda State Natural Area on the Oregon coast on May 8, 2023. Photo courtesy Oregon Parks and Recreation Department
    A second sinkhole was discovered in Cape Kiwanda State Natural Area on the Oregon coast on May 8, 2023. Photo courtesy Oregon Parks and Recreation Department
  • A second sinkhole was discovered in Cape Kiwanda State Natural Area on the Oregon coast on May 8, 2023. Photo courtesy Oregon Parks and Recreation Department
    A second sinkhole was discovered in Cape Kiwanda State Natural Area on the Oregon coast on May 8, 2023. Photo courtesy Oregon Parks and Recreation Department
  • A second sinkhole was discovered in Cape Kiwanda State Natural Area on the Oregon coast on May 8, 2023. Photo courtesy Oregon Parks and Recreation Department
    A second sinkhole was discovered in Cape Kiwanda State Natural Area on the Oregon coast on May 8, 2023. Photo courtesy Oregon Parks and Recreation Department

Park staff learned about the new sinkhole through a photo posted on social media late Monday evening. The sinkhole had formed within the fence that had been placed around the first sinkhole. 

The park has since expanded the safety fence around both sinkholes to keep park visitors at a safer distance. 

“We ask that visitors respect this barrier and all park safety barriers and that they keep pets on leashes and children away from the edges. We are monitoring the site daily, but it’s a dynamic environment. The soft sandstone cliffs can give way without warning, which is why it’s important to respect safety fences everywhere in the park,” said Park Ranger Supervisor Travis Korbe.

Park officials believe the second sinkhole appeared sometime between 10 a.m. and 7:30 p.m. on Monday. 

Tillamook County’s sandstone outcropping — where the sinkholes formed — is a rare and fragile geological formation for the Oregon Coast. Elkins told KOIN in January the sandstone is naturally much weaker and more prone to sudden collapse than the isles of basalt that dot the Oregon coastline. 

Oregon Parks and Recreation Department is working with a geologist to determine the best area to place a permanent safety fence to keep visitors away from the sinkholes. 

“The soil appears to be falling into large, unstable voids beneath the cliff caused by strong ocean waves,” Knowlton wrote in a press release. 

State park officials warn that even though there’s a fence around the sinkholes, the area could change at any moment and more sinkholes could appear. Anyone who sees a new sinkhole should report it to Cape Lookout State Park staff at (503) 842-4981.