CENAPRED reported that emissions of steam-and-gas from Popocatépetl were visible during 2-8 January. On 5 January, a steam-and-gas plume with low ash content was reported. An altitude of the plume was unknown due to cloud cover. About two hours later, CENAPRED received reports of slight ashfall in Paso de Cortés, about 7.5 km N of the summit.

Based on information from the Mexico City MWO and observations of satellite imagery, the Washington VAAC reported that an ash plume rose to an altitude of 7.3 km (24,000 ft) a.s.l. and drifted E, NE, and SE on 5 January.

Geological Summary. Volcán Popocatépetl, whose name is the Aztec word for smoking mountain, rises 70 km SE of Mexico City to form North America's 2nd-highest volcano. The glacier-clad stratovolcano contains a steep-walled, 400 x 600 m wide crater. The generally symmetrical volcano is modified by the sharp-peaked Ventorrillo on the NW, a remnant of an earlier volcano. At least three previous major cones were destroyed by gravitational failure during the Pleistocene, producing massive debris-avalanche deposits covering broad areas to the south. The modern volcano was constructed south of the late-Pleistocene to Holocene El Fraile cone. Three major Plinian eruptions, the most recent of which took place about 800 CE, have occurred since the mid-Holocene, accompanied by pyroclastic flows and voluminous lahars that swept basins below the volcano. Frequent historical eruptions, first recorded in Aztec codices, have occurred since Pre-Columbian time.

Sources: Centro Nacional de Prevencion de Desastres (CENAPRED), Washington Volcanic Ash Advisory Center (VAAC)