CENAPRED reported that during 23-29 May gas-and-ash plumes from Popocatépetl rose up to 2 km above the crater and drifted in multiple directions. Cloud cover occasionally prevented observations of the plumes. Ashfall was reported in San Pedro Benito Juarez (10-12 km SE) and Huejotzingo (27 km NE) on 23 May, and in Atlixco (23 km SE) and San Pedro Benito Juarez on 25 May. Incandescent fragments ejected from the crater landed on the flanks during 23-26 May. Incandescence from the crater was visible on 27 May. The Alert Level remained at Yellow Phase Three.

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)