Mauna Loa lava flow significantly slows; could be at least a week until it reaches key highway

Published: Dec. 1, 2022 at 5:49 AM CST|Updated: Dec. 1, 2022 at 1:39 PM CST
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KAILUA-KONA, Hawaii (KHNL/Gray News) - Hawaii Volcano Observatory scientists said the lava flow from Mauna Loa is moving at a slower pace as it spreads into flatter area.

If it continues at the rate it is flowing right now, officials said that it could take at least one week until the flow reaches Daniel K. Inouye Highway. The key thoroughfare connects Hilo and Kona.

In a news conference on Thursday, officials said the lava flow is about 3.3 miles from the highway and is moving at about 30 to 40 yards per hour.

“It has hit the flats and it has really slowed down quite considerably. The latest I’ve heard is it will most likely be over a week,” Hawaii County Mayor Mitch Roth said. “If it continues at the rate that it’s flowing right now, we’re in pretty good shape.”

Ken Hon, Hawaiian Volcano Observatory scientist-in-charge, said the lava slow is expected to become more variable as it spreads across the flat area — at times appearing to move faster or not moving at all.

“It’s hard to say if this flow will be sustained throughout the eruption or eventually if that supply to that fissure dwindles,” Hon said. “It’s also possible that it may shift and more lava could come out of fissure 4. These are just things we don’t know at this point but are subject to change.”

Lava is seen Tuesday on the Big Island from Saddle Road. (Source: @THEBARPILOTS/TMX/CNN)

He emphasized it is unknown if the lava flow will reach the highway at this point, but the provided time reference allows people to prepare in advance if the road should be blocked off.

Experts said it is unknown how long this eruption will last.

“Typically, these rift eruptions run their course after two to three weeks, but there have been some that have gone over a year and some that are much shorter than that,” Hon said. “If we saw the amount of lava decreasing rapidly, that could be an indication we’re getting towards the end of it.”

Hawaii Civil Defense said monthly siren testing will take place on Thursday and ensured residents that the alert is not related to the Mauna Loa eruption.

On Wednesday, the U.S. Geological Survey said there’s a “very high probability” that lava from the Mauna Loa eruption will reach the highway and is urging residents to be prepared.

“It’ll probably come around the north side of Pu’u Huluhulu, which is right at the Mauna Kea turnoff on Saddle Road,” Hon at a news conference Wednesday.

As of 7 p.m. Wednesday, Hon said the lava had entered flat terrain and slowed down to a rate of 24 meters per hour.

“The terrain is what is slowing it down,” Hon said.

State and county officials said they’re getting ready to shut down the highway and divert traffic if needed.

Gov. David Ige said he plans to activate the Hawaii National Guard to help set up critical infrastructure and “support planning for alternative routes and help with making available bypass routes if that becomes necessary.”

Shutting down the highway, known locally as Saddle Road, will mean more traffic in communities along the Hamakua Coast, and would have a major impact on thousands of commuters. An alternative route takes much longer.

Talmadge Magno, of the Hawaii County Civil Defense Agency, said the highway has become the “main transit” between east and west Hawaii Island.

“So it’s very important,” he said.

On Wednesday morning, USGS officials said lava was about 3.6 miles from the highway and moving at a speed of .08 miles per hour. Hon said the soonest it would reach the highway would be two days.

But he added it would likely take longer than that because the lava appeared to be moving slower.

“It’s just a question of timing. It’s not that it’s going to hit in two days, but that is the fastest time right now that it could cover the road,” Hon said.

Magno added if the main highway closes, those seeking to get between Hilo and Kona would need to rely on coastal routes like Highway 19 and Highway 11.

“They’re going to be seeing an increase in traffic and it’s just going to cause congested areas to get more congested, which equates to safety as well,” he said.

Hawaii County is also creating a safe dedicated viewing area in a section within the Pohakuloa Training Area.

“There’s portions that Daniel K. Inouye Highway doesn’t follow of the Old Saddle Road alignment,” said Ed Sniffen, deputy director of highways for the state Department of Transportation. “So in the Pohakuloa Training Area, there’s a remnant of the Old Saddle Road that we didn’t follow. That portion is still paved, it still allows people to drive on and there’s areas that could be safe for people to park on.”

The move comes as spectators flood DKI and increase the risk of accidents. Just a few hours after Big Island Mayor Mitch Roth banned parking alongside the highway, a car was hit as it was driving off the shoulder to the main road. Two people were treated for minor injuries.

It’s a $1,000 fine for illegally parked vehicles. County officials say police patrols and enforcement will continue along the highway throughout the eruption.

Officials are urging people to drive safely and stay alert, especially when driving in the dark.

Meanwhile at the Pohakuloa Training area, the Army said lava has not entered a barracks section and social media posts saying that are “false.”

They added that lava has only destroyed a fence in a remote area and precautions are being taken to protect personnel and equipment.

‘Quite an inconvenience’

Kim Rodrigues has been commuting between Hilo and the Waikoloa area for 19 years.

She said the alternate routes aren’t meant for heavy traffic.

“We’re going to have to be patient,” she said.

Rodrigues wants the state to add temporary left-turn lanes or add passing lanes on the shoulder of Highway 19 to prevent backups if there are Saddle Road closures.

“It’s going to be quite an inconvenience but it doesn’t mean that our people will be cut off,” said Elena Cabatu, head of marketing at Hilo Medical Center.

The facility has 1,600 employees and a handful of them commute from the west side.

“We are taking an inventory of our employees and where they live,” she said.

Health care workers are essential, so they will have to make the drive.

Cabatu said they are helping those employees prepare for the added commute time.

Lava diversion being discussed

Hawaii Island officials have had very preliminary discussions about whether there’s any possibility to divert the lava flow ― something that has been tried (with limited success) in other places.

Those conversations were not fruitful, Magno said, without elaborating.

At a news conference Wednesday, Ige also said diverting the flow would likely be impossible.

“There is no physical way or technological way to change the course of where the lava flows,” Ige said. “The power of Mother Nature and Madame Pele overwhelms anything we can do. So we will monitor and make plans to ensure connectivity between east and west should the DK highway get overrun with lava.”

The state said closing the highway if the lava reaches it could take about six hours.

The state Department of Transportation says if necessary, it would close the highway between the 8.8 and 21 mile markers. Barricades would go up at both points and be manned by law enforcement and DOT personnel.

At this time, the highway remains open in both directions.

Already, though, flows have crossed a private road, cutting off access and power to an important global climate monitoring station. The state Department of Land and Natural Resources said lava also crossed Old Kona Highway at around 11 p.m. Tuesday. It’s a dirt road that crosses the Mauna Loa Forest Reserve.

Meanwhile, officials continued to stress the eruption does not pose a threat to downslope communities.

The Mauna Loa eruption started late Sunday after months of elevated earthquake activity.

The 13,681-foot Mauna Loa volcano had been rumbling more in the last several months, prompting many to believe an eruption was imminent. The 1984 Mauna Loa eruption also began within the Mokuaweoweo summit.

Fissures eventually opened on the mountain’s northeast rift zone, sending lava flows snaking toward the Hilo area. None of the flows reached the outskirts of Hilo by the time the eruption ended, about 20 days after it began.