The IG reported that although visual observations were occasionally limited due to cloud cover during 7-13 May, ash and steam plumes from Tungurahua were spotted most days and rose to altitudes of 5-8 km (16,400-26,200 ft) a.s.l. Ashfall was reported in areas within 8 km to the SW, W, N, and NW on 6, 10, and 11 May. On 8 May, muddy waters were reported in areas SW and S and roaring noises were audible. On 11 May, incandescence at the summit was reported along with roaring noises and blocks that rolled 1 km down the flanks. After an explosion on 12 May, windows vibrated, roaring noises were again reported, and rockfalls occurred in an area 8 km S.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG) – “Reports provided courtesy of the Smithsonian’s Global Volcanism Program and the US Geological Survey’s Volcano Hazards Program.”