Based on a pilot report and information from INSIVUMEH, the Washington VAAC reported that a diffuse plume from Fuego reached an altitude of 4 km (13,000 ft) a.s.l. and drifted NE. A hotspot over the crater was visible on satellite imagery. INSIVUMEH reported that approximately during 21-29 January, incandescent material was propelled up to 100 m above the summit and incandescent blocks rolled about 500 m S and SW down the flanks. During 26 and 29 January, incandescent blocks broke away from lava-flow fronts and rolled S towards the source of the Ceniza River.

Geological Summary. Volcán Fuego, one of Central America's most active volcanoes, is also one of three large stratovolcanoes overlooking Guatemala's former capital, Antigua. The scarp of an older edifice, Meseta, lies between Fuego and Acatenango to the north. Construction of Meseta dates back to about 230,000 years and continued until the late Pleistocene or early Holocene. Collapse of Meseta may have produced the massive Escuintla debris-avalanche deposit, which extends about 50 km onto the Pacific coastal plain. Growth of the modern Fuego volcano followed, continuing the southward migration of volcanism that began at the mostly andesitic Acatenango. Eruptions at Fuego have become more mafic with time, and most historical activity has produced basaltic rocks. Frequent vigorous historical eruptions have been recorded since the onset of the Spanish era in 1524, and have produced major ashfalls, along with occasional pyroclastic flows and lava flows.

Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH), Washington Volcanic Ash Advisory Center (VAAC)