Hawai'i Volcano Blog

Mauna Loa Eruption Day 9: Lava flow from fissure 3 continues slow march toward Saddle Road

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This story was updated at 5:42 p.m. Dec. 6.

The lava flow on Mauna Loa’s Northeast Rift Zone continues its slow march toward Daniel K. Inouye Highway, or Saddle Road.

According to a Hawai‘i County Civil Defense update Tuesday afternoon, the flow front from fissure 3 was approaching 1.5 miles from the highway. However, no field crews from the Hawaiian Volcano Observatory were able to get to the flow area Tuesday because of inclement weather, so the most recent observatory estimate hasn’t changed from the 1.75 miles reported during a press conference Wednesday morning, and the observatory in its 4:36 p.m. update still had the leading edge of the flow about 1.93 miles from the highway.

The highway remains open in both directions.

The lava flow remains active and is continuously supplied from the fissure 3 vent. No communities are currently at risk.

During Wednesday morning’s press conference, Mike Zoeller with the U.S. Geological Survey Hawaiian Volcano Observatory said the flow was moving at 21-22 yards per hour and there are no signs of the flow stopping.


During the past 24 hours, the lava flow advanced at an average rate of about 68 feet per hour, about twice the rate for the past several days. Over shorter periods, the advance rate varied from 62 to 90 feet per hour.

Advance rates may be highly variable over the coming days and weeks. On the flat ground between Mauna Loa and Maunakea, lava flows advance more slowly, spread out and inflate.

Individual lobes may advance quickly, and then stall. Additional breakouts may occur if lava channels get blocked upslope. 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.

Zoeller said USGS is using various tools to monitor the growth of the lava flow, which include satellite observations, helicopter mapping and thermal mapping.

Zoeller said they are trying to build up drone capabilities for tracking velocities of lava in the lava channels. The limiting factor with that is drones are limited to ranges of up to 3 miles. 


On Monday night, approximately 2,000 people went through the lava mitigation route on Old Saddle Road. The County expect less to come through today as it is a work day and poor weather is forecasted.

As a reminder, Hawai‘i County Mayor Mitch Roth continues to ask people to stay by their cars and not hike out onto the a‘a as it’s not safe and puts other people in danger. Civil Defense reminded the public in its afternoon update that all areas adjacent to Daniel K. Inouye Highway, Old Saddle Road and near the lava flow are closed and access is prohibited for safety reasons. Everyone is asked to stay in designated areas to avoid hazards.

The county hired security guards to help make sure people stay off Pōhakuloa Training Area lands. Additionally, 20 members of the Hawai‘i Army National Guard has been activated to help with traffic control. Their presence is expected as long as the need exists.

Nation Guard troops arrived at the lava viewing route earlier today for a briefing with County officials related to their new post along the old Saddle Road. About 10 Guardsmen will be posted along the route for 12-hour shifts beginning today, Dec. 6.

Photo courtesy of Hawai‘i County

“Guardsmen are here to help with the increased traffic along our traffic hazard mitigation route,” said Maurice Messina, director of the Hawai‘i County Parks and Recreation Department, in a press release. “They’re here to be aloha ambassadors, ensuring that motorists remain on the appropriate roadway and out of restricted areas, especially as visibility lessens with the weather.”


Roth said the County is excited to have the Guardsmen on the island to help with the response to the eruption.

“As more and more vehicles make their way through the mitigation route, it’s imperative that we prioritize the safety of every person and vehicle on the roadway, which requires manpower that we just don’t have on our own,” the mayor said in the press release. “Adequate response relies on the partnership, and we are honored to have great partners in our fellow state and federal agencies who have stepped up in this time of need to be there for the Hawaiʻi Island community.”

There was one citation issued, unrelated to the lava viewing, and no collisions Monday evening.

According to HVO, sulfur dioxide (SO2) emission rates of approximately 120,000 tonnes per day (t/d) were measured on on Monday and remain elevated at this time. The International Volcanic Health Hazard Network has detailed information about vog: https://vog.ivhhn.org/. Forecasts for the dispersion of vog can be found on the Mauna Loa Vog Forecasting Dashboard: https://vog.ivhhn.org/content/mauna-loa-eruption

Pele’s hair — strands of volcanic glass — fragments are being wafted great distances and have been reported as far Laupāhoehoe.

Tremors continue beneath the currently active fissures. This indicates that magma is still being supplied to the fissure, and activity is likely to continue as long as we see this signal.

There is no active lava within Moku’āweoweo caldera nor the Southwest Rift Zone. We do not expect any eruptive activity outside the Northeast Rift Zone.

Most recent eruption map:  https://www.usgs.gov/maps/december-5-2022-mauna-loa-eruption-map

New webcam: [M7cam] Live Image of Mauna Loa’s Northeast Flank from Mauna Kea; view is to the south [M7cam]. See https://www.usgs.gov/observatories/hvo/m7cam-mauna-loa-northeast-flank

Original post: The leading edge of Mauna Loa’s fissure 3 lava flow is approximately 2 miles from Daniel K. Inouye Highway. The highway remains open in both directions.

No communities are currently at risk.

The weather forecast for today calls for thunderstorms for the interior areas of Hawai‘i Island, to include Daniel K. Inouye Highway. Fog and rain will make driving hazardous so drive with caution.

The public is reminded that all areas adjacent to Daniel K. Inouye Highway, Old Saddle Road, and near the lava flow are closed and prohibited from access to the public for safety. Stay in designated area to avoid hazards.

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