Hawaii activates National Guard as lava from Mauna Loa slowly inches closer to critical highway

Officials in Hawaii have activated the state's National Guard to help in the response to the eruption of Mauna Loa, whose lava has been steadily oozing toward a critical highway for days.

The fountains of lava that have been shooting from the volcano over the past week are not a threat to communities or property, officials have maintained. Still, the eruption of the world's largest active volcano has put residents and officials on edge as molten rock continues to flow toward Daniel K. Inouye Highway, threatening to shutter at least part of the shortest route linking the east and west sides of the Big Island.

"Gov. David Ige and Maj. General Kenneth Hara activated 20 Hawai'i National Guard service members on Monday and placed them on active duty to assist Hawai'i County with traffic control and other roles in the Mauna Loa eruption," Hawaii's Emergency Management Agency said in a statement.

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As of Monday, the lava was about 2.16 miles from the highway, known locally as Saddle Road, according to the U.S. Geological Survey. And the pace at which the lava moves has been unpredictable, making it challenging for experts to forecast a specific day when or if it could reach the highway.

"There are many variables at play and both the direction and timing of flow advances are expected to change over periods of hours to days, making it difficult to estimate when or if the flow will impact Daniel K. Inouye Highway," the geological survey said.

Over roughly the past day, lava has been advancing toward the highway at a rate of 25 feet per hour, a reduction from 40 feet per hour over the weekend, according to the geological survey. "Though the advance rate has slowed … the lava flow remains active with a continuous supply from the fissure 3 vent."

The last time Mauna Loa erupted was in 1984, when its lava reached about 4.5 miles from Hilo, the Big Island's largest population centre. Standing at about 13,681 feet above sea level, the volcano covers half of the island of Hawaii, according to the geological survey.

Mauna Loa began erupting again on Nov. 27, joining nearby Kilauea, which has been erupting since last year. Both volcanoes are located inside Hawaii Volcanoes National Park, which remains open as it urges spectators to view the dual eruptions safely.

"Stepping into week two of the Mauna Loa eruption. Two volcanoes, two eruptions, one park. It was another "glowrious" morning today!" the park said in an online post Monday.

Length of eruption is unknown

As officials work to determine if or when the lava flow will reach the major highway, a volcano expert said the length of eruption will play a major role in what happens.

"We don't know how long this eruption is going to last, and that will dictate whether or not the highway becomes more threatened," said Natalia Deligne, a volcanologist with the U.S. Geological Survey at the Hawaiian Volcano Observatory.

Closing the road would lengthen residents' commutes by hours, creating "a tremendous inconvenience," Ige told CNN Saturday.

Still, many have flocked to see the rare sight of two volcanoes erupting just 21 miles apart.

For many Native Hawaiians, the eruption of volcanoes holds incredible spiritual significance.

On Friday, Ku'ulei Vickery, a native Hawaiian and a teacher at a nearby public school, was among those who witnessed the glowing orange molten rock flow. She performed a traditional Hawaiian chant and left rosemary grown in her backyard as an offering.

"As a native, I'm acknowledging the space that I am in. I'm acknowledging the goddess Pele, and the people who have come before me, my ancestors," she said. "You don't go to anyone's house empty-handed. So, this is what I brought."

To accommodate the many residents and tourists drawn to the volcano eruptions, officials created a safe viewing spot on a one-way route accessible through the Daniel K. Inouye Highway, the Hawaii County Civil Defense Agency said.

Officials have also been imploring the public to be aware of the potential dangers the eruptions pose to air quality.

Volcanic emissions include sulphur dioxide, which reacts with other elements in the atmosphere and can begin to form fine particles which cause vog, a type of volcanic air pollution known as volcanic smog.

"Vog creates the potential for airborne health hazards to residents and visitors, damages agricultural crops and other plants, and affects livestock operations," according to the USGS.

The National Park Service is urging vulnerable groups, typically including the elderly and children, to be careful when viewing the dual eruptions.

"People with pre-existing respiratory conditions are especially sensitive to poor air quality and should check the air quality alert before visiting," the park service said.