The June 27 lava flow, which recently sped up, is anticipated to reach Pahoa Village Road in less than two weeks, according to Hawaiian Volcano Observatory.
HVO geologists said Wednesday evening they were anticipating the flow would reach the road, the main street for the community of about 945 people, within 13 days, or 11 days from today.
An overflight today will determine whether that estimate is adjusted.
Based on topography, the flow appears all but certain it will reach Pahoa if it doesn’t stop.
Kevin Dayton, Hawaii County spokesman, said the flow was 2.4 miles from the road and 2.5 miles from Highway 130 as of Thursday morning.
An evacuation order hasn’t been given, and Dayton said residents and business owners will be given notice within days of the flow reaching Pahoa.
The flow is passing through a forested portion of Kaohe Homesteads and it doesn’t appear it will threaten homes until it reaches Pahoa.
The county is constructing two alternate routes in case the flow, which has not showed signs of stopping, reaches the highway.
Railroad Avenue, which has been an overgrown path between subdivisions, will run from Nanawale Estates to Hawaiian Paradise Park. It is expected to be made ready for traffic by Wednesday.
Government Beach Road, a jeep trail in areas, is expected to be available for use a week later.
The routes won’t open until lava reaches the highway, though improvements will continue if more time is available, Dayton said.
The cost of the routes is estimated to be between $1.2 million and $2 million.
Dayton said that was increased by more than $400,000 after adjustments were made for the cost of materials and equipment maintenance.
Estimates for when the flow would reach Pahoa have changed a few times as geologists continue to track its progress, determined largely by topography.
Janet Babb, HVO spokeswoman, said Thursday the flow has been following a more narrow channel during the past few days, which has allowed its daily rate of advancement to increase to 400 yards as of Thursday.
That’s faster than the average daily flow rate of 320 yards between Monday and Wednesday, and 235 yards per day from last Friday through Monday.
The volume of lava coming from Pu‘u ‘O‘o hasn’t changed, Babb said.
“I think we can expect the (flow’s speed) to fluctuate … which we’ve been seeing, depending on the downhill path it takes,” she said.
Should lava reach the highway, traffic will be diverted through HPP, and county Public Works Director Warren Lee gave the large subdivision an update on its plans Wednesday evening.
In addition to the widening and compacting of the alternate roadways, the county is planning to offer a series of detour signs, temporary traffic lights and more to optimize traffic flow, Lee said.
“We have a traffic control plan,” he said. “We want to keep traffic on the main routes.”
Impacts to HPP are likely to be severe, said Jerry Carr, chairman of the neighborhood’s HPP Emergency Access Road Committee.
“Some of us are going to be more impacted than others,” he said. “It’s going to take patience, and it’s going to take a lot of effort on everyone’s part in order to make this work with the least amount of disruption as possible.”
Traffic in Nanawale Estates, Hawaiian Beaches and Hawaiian Shores is also expected to increase greatly with the alternate routes.
More than 7,000 vehicles travel the highway near Pahoa each day.
Staff Writer Colin M. Stewart contributed to this report.
Email Tom Callis at tcallis@hawaiitribune-herald.com.
