A popular lava tube in Hilo is safe to reopen after a rockfall, according to county officials and geologists.
On Sept. 23, a visitor to the popular Kaumana Caves park reported that some boulders appeared to have fallen from the cave ceiling. While nobody was injured, the entire park — and, subsequently, the nearby parking area — was cordoned off and closed to the public.
At the time, Hawaii County Parks and Recreation Director Maurice Messina said that he wasn’t sure when, or even if, the park would reopen. But on Wednesday, he confirmed the cave will reopen, although the question of when is still up in the air.
Messina explained that on Nov. 3, he visited the site with Parks and Rec Area Maintenance Supervisor Hurcules Lee and Hawaiian Volcano Observatory Scientist-in-Charge Ken Hon. The three of them, along with a team of HVO and University of Hawaii at Hilo geologists, inspected the cave and discussed how it could be reopened safely.
The team presented its findings to Mayor Mitch Roth, who determined that the cave could be safely reopened after implementing appropriate safety measures, Messina said.
“We feel that we’re going to be able to reopen the cave to the public once we add some signage warning about the inherent risks of being in the cave,” Messina said, adding that there is no concrete date for when those signs will be added.
The signage will include warnings about potential cave hazards and advise visitors to enter at their own risk and bring appropriate equipment, such as close-toed shoes, flashlights and long pants.
Hon said the cave — a lava tube formed during a Mauna Loa lava flow in 1881 — poses, like all caves, certain hazards such as the potential for rockfalls or flooding that must be taken into account by visitors, who should use appropriate discretion when entering.
“It’s a wild cave that has not been maintained, and there’s naturally going to be certain risks,” Hon said. “I’ve taken students there to visit the cave, and they’ve always been wearing helmets.”
Hon told the Tribune-Herald his inspection on Nov. 3 only found a single area of recent scarring on the lava tube walls — presumably, the site where the rocks fell from on Sept. 23, although he added that the actual fallen rocks were not there when he visited.
Based on the scars, Hon said the rocks appeared to be only about 1- to 2-feet wide, relatively small for a cave rockfall, but obviously dangerous for anyone beneath them.
That rockfall did not coincide with any observed seismic event, Hon said.
However, Hon added that the cave is “quite a beautiful resource,” saying it is probably the youngest lava tube available to visitors in the United States, being less than 100 years old. He noted that people were using the tube to dump trash until some time in the 1970s, when the county government led a cleanup effort to open the cave as a park.
“The county has done a remarkable job cleaning up the tube and keeping it safe,” Hon said.
Email Michael Brestovansky at mbrestovansky@hawaiitribune-herald.com.