Mauna Loa Observatory Road Reopens in 2026, More Than Three Years After 2022 Eruption

The road to NOAA’s Mauna Loa Observatory reopened on March 26, 2026, more than three years after the November 28, 2022 eruption buried roughly 6,000 feet of the access road under an average of 30 feet of rock. 2 miles of hardened lava. The eruption also carved two canyons through the main channels and destroyed the power lines feeding the site.

Technicians reached the observatory only by helicopter for more than three years. Within ten days of the eruption, NOAA and University of Hawaii staff installed backup CO2 instruments on neighboring Mauna Kea. By mid-2023, rooftop solar and batteries had restored limited power to a handful of buildings.

As of the article date, 62 of the 91 daily measurement programs at the observatory are running again. " In early 2025, the Department of Government Efficiency placed the lease on NOAA’s Hilo support office on a list of more than twenty agency leases proposed for termination. The reported annual saving from terminating the lease was about $150,692.

The Hilo office has a staff of eight who run the program, process the data and stage the trips up the mountain. The issue involving the lease of an auxiliary facility in Hilo was resolved in July 2025, a NOAA spokesperson said. On August 28, 2025, Hawaii’s congressional delegation introduced a resolution honoring the observatory’s nearly seven decades of work and reaffirming support for the Hilo office by name.

The lease on the Hilo support office was reported to expire on August 31, 2025. For fiscal year 2026, the administration proposed cutting NOAA’s budget by roughly 25 percent and eliminating the Office of Oceanic and Atmospheric Research. The appropriations bill signed into law in January 2026 retained the research office, funded NOAA at roughly $6 billion and directed the agency not to close its laboratories.

R. 6938) which became law in January 2026, a NOAA spokesperson confirmed. NOAA announced in May 2026 that the Mauna Loa site was being reopened, rebuilt and expanded.

The redevelopment plan includes upgrades to the historic Keeling Building, a new 130-foot instrumented sampling tower, expanded laboratory space, campus-wide fiber, new power and battery systems and a dedicated outreach space. A construction plan frozen since 2023 is now proceeding in 2026 because the road reopened.

Measurements from Mauna Loa Observatory have produced the Keeling Curve since 1958.

The observatory sits more than 11,000 feet up the slope of Hawaii's largest volcano.