State officials assured the public that the slope between the two Pali tunnels is now stable after a rockfall during the peak, morning commute hours Monday damaged several vehicles in the highway’s Honolulu-bound lanes.
Police responded to the landslide shortly before 7:20 a.m. Monday, closing the Honolulu-bound lanes and eventually the Kailua-bound lanes as well.
Rocks between the size of baseballs and basketballs as well as debris rained down, according to Ed Sniffen, deputy director of the state Highways Division, damaging four vehicles, one of which had to be towed. No injuries were reported.
“It wasn’t a significant portion of the slope that came down,” said Sniffen. “It was more of a rockfall.”
Sniffen said police responded and cleared the road quickly Monday morning. The Honolulu Fire Department also responded to the scene.
The state then sent geotechnical engineers and rock scalers up to inspect the slope, resulting in the closure of both directions at about 9 a.m. The team determined the slope was clear of other hazards before reopening Kailua-bound lanes at about 11:25 a.m. and reopening all lanes at about 12:30 p.m.
“We assessed the area. It’s safe,” said Sniffen at a news conference. “We looked at the slopes, the lower portions, the upper portions. We’re very comfortable that it’s safe. Definitely, if there’s going to be any other events that come through, weather or otherwise, we’ll take a look at it again.”
The state will further assess the area in the next few weeks, he said, and most likely will install impact fences in the area to make sure any other rockfalls do not cause damage. He did not have estimated dimensions for the fence, pending further assessment, but said it would not affect any lanes on the highway.
The slope was last assessed by the state in 2012 and updated in 2015, he said.
On Oahu, Pali Highway between mile point 5.7 and 5.9 near Monday’s rockfall is No. 2 on a state list of priorities for rockfall mitigation. Other portions of the highway are ranked Nos. 3 and 4. Kamehameha Highway near Waimea Bay is No. 1.
Statewide, Pali Highway is Nos. 8 and 9 on a list of top 10 rockfall mitigation sites.
A state hazard mitigation plan, which examines landslide events, including rockfalls and mudslides that occurred in Hawaii from Jan. 1, 2012, through Dec. 31, 2017, listed Pali Highway among the 10 top rockfall hazard sites in Honolulu County. Other highways listed included Kalanianaole, Kamehameha and Farrington highways.
The last rockfall on Pali Highway occurred in 2016 following a storm, according to Sniffen, and was more severe than this one.
A net mesh project already has been planned for various highway areas, but at this time the state is prioritizing the slope between the Pali tunnels due to the recent rockfall and will consider installing a fence, Sniffen said.
State Department of Transportation spokesman Tim Sakahara encourages motorists to check goakamai.org for real-time traffic conditions, which recently expanded to include Windward side highways.
TOP 10 ROCKFALL MITIGATION SITES STATEWIDE
1. Kamehameha Highway (Route 83) — mile point 5.4-5.5
2. Hawaii Belt Road (Route 19) — mile point 21-21.5
3. Hawaii Belt Road (Route 19) — mile point 25.8-26
4. Kuhio Highway (Route 56) — mile point 25
5. Hawaii Belt Road (Route 19) — mile point 21.6-21.9
6. Kuhio Highway (Route 560) — mile point 0.7-1.2
7. Honoapiilani Highway (Route 30) — mile point 10.3-10.4
8. Pali Highway (Route 61) — mile 5.7-5.9*
9. Pali Highway (Route 61) — mile 5.9-6*
10. Hawaii Belt Road (Route 19) — mile point 26.3-26.7
Source: State Department of Transportation
* Tied, also ranked No. 2 and 3 for Oahu
