What happens if Saddle Road is closed because of the Mauna Loa eruption?

Listen to this Article
5 minutes
Loading Audio... Article will play after ad...
Playing in :00

While there was encouraging news Thursday morning that the supply of lava flowing toward Daniel K. Inouye Highway (also known as Saddle Road) was cut off, the Mauna Loa eruption is not over.

County officials and Hawaiian Volcano Observatory scientists are still closely monitoring the volcano’s unpredictable activity.

Observatory geologist Frank Trusdell, who has spent most of his career studying and monitoring the world’s largest active volcano, advised caution Thursday: “We just have to be vigilant.”

The immediate threat is over, but there still is a possibility that molten rock could flow elsewhere down the mountain’s northeast flank and reach the Big Island’s primary east-west highway. If that happened, and Saddle Road had to be closed, it would cause serious disruption — to government, business, industry, shipping, commuting, visiting family, you name it.

The western end of Daniel K. Inouye Highway in West Hawai‘i. Photo from Wikipedia.

“As a business organization representing nearly 300 member businesses and nonprofit organizations mostly from East Hawai‘i, we are concerned about the varying degrees of impact to our members and their employees,” said Miles Yoshioka, executive officer of the Hawai‘i Island Chamber of Commerce. “Saddle Road is important to anyone who uses it because it offers safe, quicker travel between West and East Hawai‘i, whether it be for work, shopping or visiting family.”

The Daniel K. Inouye Highway is quite possibly the most important roadway on the island.


It offers a direct, fast connection between the population centers of Kailua-Kona and Hilo; and it is built to federal standards to withstand the wear and tear of larger vehicles, including big rigs carrying goods from both Big Island piers in Hilo and Kawaihae. It also provides a safer, wider route for traffic to cross the island.

“Some of our businesses have operations on both sides of the island, some of our businesses have employees that travel this route and some companies transport goods,” said Wendy Laros, president and CEO of the Kona-Kohala Chamber of Commerce. “Certainly, closure of this road would impact island businesses and residents.”

The Northeast Rift Zone eruption of Mauna Loa continues with a major change overnight Wednesday. The fissure 3 vent continues to erupt but the supply of lava appeared to be much reduced Thursday morning. Lava is overtopping channels near the vent with flows extending no farther than 2.5 miles from the fissure. The channels below this point appear drained of lava and probably no longer feed the main flow front that was nearing Daniel K. Inouye Highway, or Saddle Road. U.S. Geological Survey image by M. Patrick.

Multiple agencies and industry sectors on the island are taking geologist Trusdell’s advice and continuing to make plans for a possible closure of Saddle Road.

Yoshioka said a closure of the highway would mean greater use of Highways 19 and 11, narrower roadways that circle the island, one heading north out of Hilo and the other to the south, respectively. Motorists would encounter heavier traffic, reduced speeds and more distance to travel between the east and west sides of the island compared to using Saddle Road.

Travel time would increase not just between the east and west coasts, but everywhere on the island.

U.S. Geological Survey map/image

“Drivers would need to slow things down and be more careful,” Yoshioka said.

Some businesses have been planning for a possible closure of Saddle Road for more than week, and retailers and warehouses with several outlets around the Big Island have been making sure their shelves are stocked to the brim and stockpiling high-need goods. Some also have been strategically diverting goods to the Kawaihae or Hilo piers, depending on their needs.

“Trucking and shipping companies are staying proactive and having discussions with the state and Hawai‘i Department of Transportation regarding lifting large commercial restrictions over the bridges along Hāmākua Coast and how those restrictions and limits will be regulated, aware that Highway 19 may become a major thoroughfare for goods traveling to East Hawai‘i,” Yoshioka said.

Shipping companies save time using the Daniel K. Inouye Highway, which reduces costs attributed to employee wages and benefits, according to one company he spoke with, saving it more on labor costs than fuel.

“Shippers are assuring us that accommodations will be made regarding the intra-island transport of goods,” Yoshioka said.


Keoni Wagner, spokesman for Honolulu-based shipping giant Matson Inc., said a closure of Saddle Road wouldn’t have a large impact on the company’s flow of cargo on the island.

Kawaihae Harbor. File photo.

“We primarily use Kawaihae Harbor for our barge service to the Big Island and our trucking partners mostly use Saddle Road to connect cargo to and from the Hilo side,” Wagner said. “If Saddle Road isn’t available, they have the northerly and southerly routes as alternatives, which would just add a little transit time — nothing significant.”

He added that Matson is prepared to modify its terminal hours as needed to accommodate changes like a closure of the highway. The shipping company also remains in close contact with the Hawai‘i County mayor’s office and State Highways Division about contingencies in the event that it must adjust.

For others, not having the use of Saddle Road would have more ramifications.

“Some businesses with employees who travel to work from East Hawai‘i to West or vice-versa are making accommodations for those employees whether it may be offering weekly accommodations to reduce the amount of travel time for the hotel employee or possible remote work options for others,” Yoshioka said.

He added that Hele-On, the County’s public transportation system, also has a bus route from Hilo to the Kona Coast that transports residents who work at the Kona-side resorts. Closure of Saddle Road would severely impact those bus riders, especially their wallets — the bus is free to ride.

A shared concern with a long-time road closure is will employees unable to get to their jobs seek employment elsewhere closer to home? With nearly every industry already affected by an ongoing employee shortage, that could severely impact some businesses, Yoshioka said.

One sector that could particularly feel the pain from a closure of the highway is astronomy.

Maunakea observatories. Courtesy file photo.

Access to the observatories could be severely restricted depending on where a closure would be put in place. Yoshioka said if a closure takes place on the Hilo side, where the majority of the observatory base facilities are located, employees might not be able to get to the telescopes without going from the Kona side. Two base facilities in Waimea would be affected by a more west-side closure.

“We are working closely with all relevant authorities to do comprehensive contingency planning for a range of possible scenarios,” said Mari-Ela Chock, communications officer for W.M. Keck Observatory, which has telescopes atop Maunakea. “At this time, there is no indication that Maunakea facilities nor the [Maunakea Access Road are in] danger, so we are focusing on our people having access to the observatories.”

Chock said planning includes looking for ways for employees to make their commute and work times manageable. Many of the telescopes on the mountain can be operated remotely; however, there are certain tasks that require an on-site presence — instruments that operate at extremely cold temperatures need their cryogen tanks refilled in person regularly to prevent them from warming up and avoid potential damage. Day-to-day preventative maintenance for the facilities is critical.

“We have contingency plans in place where [we] can pare down to only essential employees on the mauna if that becomes necessary,” Chock said.

There is an average of 50 to 75 Maunakea Observatories employees working on the mountain every day. Part of those contingency plans include modified schedules and adjusted work tasks that can be done remotely or at the headquarters of each observatory.

It’s also possible that a closure of Saddle Road could cause some scientific observations or research to be delayed. Chock said the observatories are assessing immediate and long-term impacts to their ability to carry out their scientific mission and are in contact with their colleagues around the globe who depend on the research done on Maunakea.

“We have been through shutdowns before and in the past, we have always kept everyone engaged and working,” she said.

But the concern isn’t just about the limitations on the observatories’ work and staffs.

“We must also carefully monitor the operational impacts of volcanic ash, Pele’s hair, [sulfur dioxide], humidity and other environmental concerns,” Chock said. “Also, utilities to the observatories must remain reliable. Under certain circumstances, difficulties with these factors could require us to halt operations.”

The decision-making framework the observatories use is grounded in their priorities, with the safety of people top priority — staff, their families and the entire community.

“Our telescope facilities and instrumentation are our second priority and science observing and projects are third,” Chock said. “We understand the power, awe and cultural significance this eruption has for everyone in our community. We are committed to keeping safety as our top priority. We’ll continue to keep in constant communication with the Maunakea Stewardship and Oversight Authority, the University of Hawai‘i, [Hawai‘i County] Civil Defense, Department of Transportation, the County of Hawai‘i and other entities to remain informed of changing travel conditions due to the lava flow and also the many visitors filling up local roads.”

Hawai‘i County Mayor Mitch Roth said during Wednesday’s media briefing about the eruption that discussions are underway for plans if and when lava were to reach the highway, but reiterated there are a lot of variables to take into account.

The decision to close Saddle Road would be made based on where an active lava flow front is located, how much time it would take that lava to get to the highway, and safety concerns. There’s not one simple development that would lead to the closure of Saddle Road.

“It’s still a very fluid situation,” Roth said.

Hawai‘i County Mayor Mitch Roth

County discussions have included talks about where the road could be closed if the lava crosses, possibly near the 8- or 10-mile markers on the highway on the Hilo side and somewhere near the bottom of Saddle Road on the Kona side, but no definitive decisions have been made.

Hawai‘i County Civil Defense Administrator Talmadge Magno said during Thursday’s press conference that the agency knows the circumstances and behaviors of eruptions can change.

“We’ll stay operational and in close contact with Hawaiian Volcano Observatory to monitor any changes,” Magno said Thursday. “The main thing here is that no communities are threatened, and we’ll continue our planning and monitoring.”

Roth said: “We’re gonna continue to prepare because we still have an active volcano.”

Coordination between the Department of Transportation and Hawai‘i County is also ongoing to maintain safe access to transportation infrastructure, including notification of road closures in the event conditions such as heat or lava make crossing of the Daniel K. Inouye Highway unsafe.

The department said in a press release Wednesday that plans and conditions to reopen the road if it is impacted by lava have been discussed. In anticipation for increased use, repairs to bridges on Hawai‘i Belt Road (Highway 19), one of the alternate routes between Hilo and Kona, also were completed and returned to the unposted weight limit of 40 tons.

Plans for messaging in the area and equipment are in place if it becomes necessary to close the heavily used roadway and divert traffic, the Transportation Department said in a Nov. 29 press release. Magno said last week during a press conference that it would take about six hours to close the highway if necessary.

The state also already has a preliminary plan for the possibility of closing the highway.

The Hawai‘i Department of Transportation’s preliminary plan for the possibility of closing Saddle Road.

The Hawai‘i Emergency Management Agency deployed a four-person Emergency Management Assistance Team to Hilo last week to support Civil Defense. The team is helping with operations, planning and logistical challenges during the eruption. It also is assisting with any needs the County identifies that can be quickly matched up with available resources and data.

The agency is in daily contact with an array of partners who have detailed knowledge of the aspects of the Mauna Loa eruption and its consequences, actual and potential, including the U.S. Geological Survey, the Department of Transportation and Civil Defense, according to Adam Weintraub, communication director for the state emergency management agency.

“Cutting the highway or other critical infrastructure could affect economic activity, increase commute times, complicate delivery of goods and services or a whole host of other potential consequences,” said Luke Meyers, administrator of the Hawai‘i Emergency Management Agency, in a Dec. 2 press release. “As part of [Hawai‘i Emergency Management Agency’s] support role, we’re developing a blueprint that can be used to anticipate and mitigate those consequences, and maybe even prevent some of them.”

Hawaiian Electric also is watching the eruption closely.

Eastbound traffic was bumper-to-bumper Nov. 30 on Saddle Road toward Gilbert Kahele Recreation Area as droves of people flocked to see the historic eruption of Mauna Loa. File photo by Cammy Clark/Big Island Now.

“We want to assure the community that we’re ready and able to respond,” said Kristen Okinaka, spokeswoman for electric utility, in a Dec. 1 press release. “Because of the unpredictable nature of the flows, we’re developing several plans to keep power on and will put into action the plan that best fits the situation. The safety of employees and community is our top priority.”

Plans include, but are not limited to:

  • Rerouting power if lava impacts transmission lines on Saddle Road.
  • Completing critical maintenance work.
  • Ensuring sufficient fuel supply for company-owned facilities and vehicles.
  • Assessing alternate driving routes for outage response.
  • Staging areas for vehicles and equipment.

Laros said the hope is that the eruption will cease or slow down without ever reaching the highway.

“We continue to be a resource of information for our members, either providing reliable information from government sources or connecting members with other businesses who can help them with their particular needs,” Yoshioka said. “We also share information about our member businesses and nonprofits, which may be relevant to a wide segment of our community.”

Nathan Christophel
Nathan Christophel is a full-time reporter with Pacific Media Group. He has more than 25 years of experience in journalism as a reporter, copy editor and page designer. He previously worked at the Hawaii Tribune-Herald in Hilo. Nathan can be reached at [email protected]
Read Full Bio

Sponsored Content

Subscribe to our Newsletter

Stay in-the-know with daily or weekly
headlines delivered straight to your inbox.


This comments section is a public community forum for the purpose of free expression. Although Big Island Now encourages respectful communication only, some content may be considered offensive. Please view at your own discretion. View Comments