CENAPRED reported that each day during 16-23 November there were 9-29 steam-and-gas emissions from Popocatépetl that drifted NW, NE, and E. At 1714 on 19 November an explosion generated an ash plume that rose 2 km above the crater rim and drifted NE. A minor explosion at 0230 on 21 November generated an ash plume that rose 600 m and drifted NW, and at 0136 the next morning another small explosion produced an ash plume that rose 800 m and drifted NE. The Alert Level remained at Yellow, Phase Two (the middle level on a three-color scale).

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.

Source: Centro Nacional de Prevencion de Desastres (CENAPRED)