CENAPRED reported that there were 65-288 daily steam-and-gas emissions, sometimes containing ash, and daily explosions at Popocatépetl during 26 April-2 May. Ash-and-gas plumes drifted ENE. On most days webcam images showed nighttime incandescence in the crater and from material that had been deposited on the upper flanks. A moderate explosion at 0109 on 26 April ejected material that landed on the N flank as far as 1 km from the crater rim. A minor explosion was recorded later that day at 1817. A moderate explosion at 0116 on 27 April ejected incandescent material onto the upper flanks. Another moderate explosion was recorded at 1147 and minor explosions were recorded at 0348, 0606, 0857, and 1059. Minor explosions continued to be detected during the rest of the week: at 0857 and 1750 on 28 April, 0150 and 2350 on 29 April, at 2205, 2220, 2256, and 2345 on 30 April, and at 0000, 0130, 0356, 0454, and 0506 on 1 May. A moderate explosion occurred at 1249 on 30 April. On 2 May minor explosions occurred at 0335 and 0942. According to the Washington VAAC ash plumes were identified in satellite images daily rising 5.8-7.3 km (19,000-24,000 ft) a.s.l. (0.4-1.9 km above the crater rim) and drifting NE, E, and SE. 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.

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