Safety concerns for motorists resurfaced yesterday six years after unstable hillside conditions forced state officials to shut down Kamehameha Highway for 95 days after a rockslide near Waimea Bay.

"It shows we're still vulnerable," said Bodo Van Der Leeden, a city Ocean Safety captain and 30-year North Shore resident. Yesterday's early-morning slide of rocks and debris, including at least one tree, closed a section of Kamehameha Highway from 4 a.m. to 9 a.m. No injuries were reported.

About a dozen rocks fell from the top of the hillside, including a truck-engine-sized boulder that rolled onto the roadway, said state Department of Transportation spokesman Scott Ishikawa.

Chain-link fencing and netting that the state had installed to protect motorists from falling rocks after the March 2000 slide did its job, but the boulder and debris that made it to the highway yesterday came through an unprotected area on the Pupukea side, according to Ishikawa.

"The fence took a beating," he said, and it may need to be replaced.

The state put up 3-foot-high concrete barriers in the previously unprotected stretch where the boulder fell yesterday, Ishikawa said.

Transportation Director Rod Haraga said the ground remains saturated from seven weeks of heavy rains in some high-impact areas, increasing the threat of falling rocks.

"The amount of rain washed away soil around boulders, so they can be dislodged," he said. "The worst conditions are saturated soil conditions."

His department has been working on a statewide rockfall mitigation plan by identifying potential trouble spots such as Hana in east Maui, and the Hale'iwa end of Waimea Bay and Kailua Road on O'ahu.

Additionally, there are several sites on the Big Island and one on Kaua'i, Haraga said.

Setting up barriers is a stop-gap measure until officials can find a permanent fix, he said.

Reach Rod Ohira at rohira@honoluluadvertiser.com.