Work on the Thurston Lava Tube exit has been extended, the National Park Service said, and the exit will remained closed until Aug. 21.
The work began when the NPS replaced an old electrical line. The exit trail, which runs about 700 feet, will be repaired.
It will remain open, although people will have to use the entry as both entrance and exit.
The restrooms will remain open, but Escape Road will remain closed during the project.
“Thurston Lava Tube, or Nahuku, is one of the most popular features in the national park,” the NPS said. It is an ancient lava tube set in a tree fern forest.
The NPS advised visitors to try to visit in the early morning or late afternoon to avoid the congestion from about 10 a.m. to 2 p.m.
“The park regrets any impact to visitors and residents. Dates and times are subject to change, and the public will be notified if changes are necessary,” they wrote.