Based on analyses of satellite imagery and a pilot observation, the Washington VAAC reported that on 20 October an apparent ash plume from Fuego drifted SSW. On 21 October, multiple ash emissions resulted in an ash cloud that drifted 55 km S. Emissions were also reported the next day. On 26 October, a diffuse gas-and-ash plume drifted W. That same day, INSIVUMEH reported that explosions produced plumes that rose to altitudes of 4.4-4.8 km (14,400-15,700 ft) a.s.l. and drifted 10 km S and SW. Ash fell downwind, rumbling and degassing sounds were reported, and avalanches of blocks descended the flanks. On 27 October, a few ash clouds seen on satellite imagery drifted 90 km NW.

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