Waimea Valley nature park will be closed for several weeks while engineers work to remove debris from two rockslides and stabilize the steep slopes of the North Shore valley.

About 2 cubic yards of rocks fell on a service road early Sunday morning, cutting off all electrical power into the valley.

The rockfall came three weeks after a larger landslide blocked the main entry road with 150 cubic yards of debris that included a boulder as big as a car. The Nov. 21 rockfall interrupted electrical power and telephone and water service.

The recovery effort will be handled by Janod, an engineering firm with expertise in slope stabilization, according to an announcement by Hi'ipaka LLC, a nonprofit corporation that operates the park for the owner, the Office of Hawaiian Affairs. The recovery operation will be directed by Pierre Rousseau, who has overseen local projects including a rockfall barrier at the Fern Grotto on Kauai.

About 20 of the park's 40 employees will be out of work while the work is done, said Gail Chew, interim executive director. The company will continue to provide benefit coverage, including medical and dental plans.

Chew said Janod will begin work this week. “;We hope it will be completed by mid-January,”; she said.

The 1,800-acre park contains botanical gardens and more than 70 ancient Hawaiian archeological sites.