UPDATE: Mauna Loa lava flow only 4.5 miles from Saddle Road

This story has been updated Tuesday afternoon.

As of 3:30 p.m. Tuesday, the lava from the Mauna Loa eruption has flowed to within approximately 4.5 miles from Saddle Road — which is the main highway that runs through the center of the Big Island and is the major route between the population centers of Kailua-Kona and Hilo.

The eruption activity is concentrated on the Northeast rift zone, with four fissures currently open.

The longest and largest lava flow is fissure 3. This flow crossed the Mauna Loa Weather Observatory Road at approximately 8 p.m. yesterday evening, cutting off access and power to the facility. This observatory is one of only four NOAA laboratories in the world that measure atmospheric conditions and monitor carbon dioxide levels.

Hawaiian Volcano Observatory currently has people out in the field trying to get a better understanding on how fast the flow is moving. As of Tuesday morning, lava was moving less than a mile an hour.

Tuesday afternoon, lava fountains at fissure 3 were consistently at 131 to 164 feet tall. Lava fountains at fissure 4, which formed at about 7:30 p.m. Monday night, were 16 to 33 feet tall.

New webcam views of the Northeast Rift Zone of Mauna Loa are available at these links: 

• https://www.usgs.gov/media/webcams/m5cam-mauna-loa-fissure-3-eruption-northeast-rift-zone
• https://www.usgs.gov/media/webcams/m6cam-mauna-loa-northeast-rift-zone-uprift-view-wsw
• https://www.usgs.gov/media/webcams/m4cam-mauna-loa-northeast-rift-zone-downrift-view-ene

USGS geologist Katie Mulliken said the eruption is still behaving like flows in the past.

“The lava flows coming down that flank typically slow down because the topography levels out,” Mulliken said.

Once they hit the area where the slope becomes less steep, the flows typically go toward Hilo, but there is a chance it can go west.

“We’re monitoring the situation,” Mulliken said. “We can’t really forecast what’s going on right now.”

The eruption on Mauna Loa began late Sunday night. On Monday, Hawaiian Volcano Observatory said three fissures were fountaining lava on the northeast rift zone at 100 to 200 feet in height. At 1:30 p.m. yesterday, only the lowest was still active.

There currently is no activity in the summit caldera. There is no lava spilling to the west or in the Southwest rift zone. The Hawaiian Volcano Observatory expects no eruptive activity outside of the Northeast rift zone.

The Northeast flank of Mauna Loa is not populated. With the current direction of the lava flows, there continues to be no threat to any communities or infrastructure.

But there is a visible gas plume from the erupting fissure fountains and lava flows, with the plume primarily being blown to the North. Sulfur dioxide (SO2) emission rates of approximately 250,000 tonnes per day were measured on Nov. 28.

Because there is no threat to communities and infrastructure at this time, the emergency shelters that were opened as a precaution in Kailua-Kona and Pāhala closed at noon Tuesday.

For those traveling Saddle Road/Daniel K. Inouye Highway, parking along the highway is unsafe and prohibited.

The Hawai‘i Police Department said vehicles that park along this highway between the 16 and 31 Mile Markers will be subject to citation and will be towed.