IG reported that although visual observations were occasionally limited due to cloud cover, ash-and-steam and ash plumes from Tungurahua rose to altitudes of 6-8 km (19,700-26,200 ft) a.s.l. during 5-11 December. Plumes drifted SW, W, and NW. During 5-8 December, incandescence at the summit was observed and roaring noises and “cannon shots” were heard. During 6-7 December, incandescent material was propelled out of the crater and rolled about 1 km down the flanks. Explosions shook the ground and rattled windows in multiple areas, including at the Tungurahua Observatory (OVT) in Guadalupe, 11 km N. During 5-8 December, ashfall was reported in areas to the SW, W, and NW.
Source: Instituto Geofísico-Escuela Politécnica Nacional – “Reports provided courtesy of the Smithsonian’s Global Volcanism Program and the US Geological Survey’s Volcano Hazards Program.”