Rainfall keeps lahar hazard active at Fuego volcano after initial flows, Guatemala
Weak to moderate lahars descended from Fuego volcano, Guatemala, at 19:17 LT on September 10, 2025, moving through Barranca Ceniza and into the Zarco and Mazate rivers, tributaries of the Achíguate River. The National Institute of Seismology, Volcanology, Meteorology and Hydrology (INSIVUMEH) reported that conditions remain favorable for additional lahars on the southwestern flanks.
Fuego volcano on September 11, 2025. Credit: INSIVUMEH
A notable lahar activity was detected at Fuego volcano, Guatemala, at 19:17 LT on September 10, descending through Barranca Ceniza and into the Zarco and Mazate rivers, both tributaries of the Achíguate River.
The lahars were characterized as weak to moderate in intensity, carrying water, volcanic material, tree trunks, branches, and blocks up to 3 m (10 feet) in diameter. INSIVUMEH warns that their volume and intensity could increase with continuing rainfall on the upper slopes of the volcano.
According to subsequent reports issued on September 11, Fuego volcano remains active with weak degassing up to 200 m (656 feet) above the crater and 7–10 weak to moderate Strombolian explosions per hour. These explosions produced ash plumes that rose to 4 800 m (15 748 feet) a.s.l. and dispersed 8–10 km (5–6 miles) to the west and southwest, with ashfall reported in nearby communities.
Rainfall of 45 mm (1.8 inches) was recorded, and INSIVUMEH noted that the presence of additional rain in the late afternoon and evening could generate new lahars in multiple drainages on the volcano’s southwestern flank.
Lahars are fast-moving flows of water and volcanic debris, capable of transporting large boulders, trees, and sediment, presenting a significant natural hazard. Even moderate flows can damage roads, bridges, and farmland, and pose severe risks to communities near affected river channels.
Authorities have advised municipalities and road managers in areas such as Las Palmas, San Vicente Los Cimientos, and Escuintla to maintain vigilance, as road restrictions may be required if rainfall persists.
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