Kīlauea Episode 43 Sets Fountain Height Record as Ash Reaches Communities 50 Miles Away
Kīlauea's 43rd eruptive episode on March 10 produced record 540-meter lava fountains and sent ash across communities 80 kilometers away, prompting closures and flight cancellations as USGS forecasts Episode 44 for late March.
Overview
Kīlauea volcano’s 43rd eruptive episode sent lava fountains to a record 540 meters (1,770 feet) on March 10, 2026, the highest of the current eruption cycle that began in December 2024. The nine-hour event ejected an estimated 12 million cubic meters (16 million cubic yards) of lava from two vents on the western floor of Halemaʻumaʻu crater, while volcanic ash and tephra reached communities up to 80 kilometers (50 miles) away, prompting highway closures, national park evacuations, and flight cancellations at Hilo airport.
The episode brings the total volume erupted across all 43 episodes to approximately 250 million cubic meters (325 million cubic yards), and the crater floor has risen roughly 90 meters (300 feet) since the eruption cycle began. Scientists at the USGS Hawaiian Volcano Observatory now forecast that Episode 44 could begin between March 28 and April 14.
Nine Hours of Record-Breaking Fountains
Episode 43 began at 9:17 a.m. HST on March 10 when both the north and south vents on the western side of Halemaʻumaʻu crater floor reactivated. The north vent exceeded 100 meters by 10:00 a.m., and both vents surpassed 300 meters by 10:50 a.m. Peak fountain heights reached at least 400 meters around 11:00 a.m., with the south vent consistently producing fountains 10 to 30 percent higher than the north vent throughout the event.
The eruption column rose progressively higher during the day, reaching 10,000 feet by 10:10 a.m., exceeding 20,000 feet by 11:30 a.m., and surpassing 30,000 feet (9,100 meters) above sea level before the episode concluded at approximately 6:21 p.m. HST. The Uēkahuna tiltmeter recorded 33.7 microradians of deflationary tilt during the event, indicating significant withdrawal of magma from the shallow reservoir beneath the summit.
NASA’s Landsat 9 satellite passed overhead approximately four hours after fountaining subsided, capturing thermal imagery that showed lava covering roughly half of the Halemaʻumaʻu crater floor.
Tephra Fallout Reaches Distant Communities
Southwesterly winds carried volcanic fragments across a broad swath of Hawaiʻi Island. More than 200 tephra fall reports were submitted through the USGS “Is Tephra Falling?” webtool, with the first observations arriving around 10:30 a.m. from areas within Hawaiʻi Volcanoes National Park.
The Uēkahuna overlook accumulated 10 to 18 centimeters (4 to 7 inches) of tephra, while Kīlauea Military Camp recorded approximately 5 centimeters (2 inches). By 1:00 p.m., ash and Pele’s hair had reached Mountain View, Keaʻau, Pāhoa, and Hilo. Communities along the Hāmākua coast began reporting fallout around 2:00 p.m., with the overall fallout zone extending from Kalapana in the south to Laupāhoehoe in the north.
Portions of Highway 11 and Hawaiʻi Volcanoes National Park were temporarily closed for safety and cleanup. The aviation color code was elevated to red, and several flights at Hilo airport were canceled.
Water Quality and Public Health
The USGS also released water quality data from testing conducted after Episode 41 in January 2026. Fluoride levels in catchment tank water ranged from 0.06 to 0.3 parts per million, well below the Environmental Protection Agency’s limit of 4.0 ppm. However, roof runoff collected before cleanup showed fluoride concentrations of 7 to 10 ppm, underscoring the importance of clearing volcanic deposits from catchment surfaces before rain.
Advances in Eruption Forecasting
The episodic nature of Kīlauea’s current eruption cycle has provided volcanologists with an unusually rich dataset for refining eruption forecasting methods. Separately, recent advances in volcano monitoring are improving scientists’ ability to predict such events. A study published in Nature Communications by researchers at the Institut de Physique du Globe de Paris and GFZ Helmholtz Centre for Geosciences describes a method called “Jerk” that detected 92 percent of eruptions at Piton de la Fournaise between 2014 and 2023 using a single broadband seismometer. The system identifies extremely small ground motions, measuring only a few nanometers per second cubed, caused by magma pushing underground, sometimes providing up to 8.5 hours of warning.
Meanwhile, distributed acoustic sensing (DAS) technology deployed on fiber-optic cables in Iceland has demonstrated the ability to provide 30 minutes to several hours of advance notice before eruptions on the Reykjanes Peninsula. Led by Caltech geophysicist Zhongwen Zhan and published in Science, the approach uses existing telecommunications infrastructure to detect magma movement with millimeter-scale resolution.
These monitoring advances arrive as Kīlauea’s current eruption cycle shows no signs of abating. Summit inflation recorded since Episode 43 ended indicates that magma continues to accumulate beneath the surface, and USGS models place the preliminary forecast window for Episode 44 between March 28 and April 14, 2026.