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 27 November-4 December. During 28 November-1 December, seismic activity was elevated and multiple explosions were associated with almost continuous emissions of steam and ash. Explosions and “cannon shots” vibrated large windows and the ground within a 13 km radius of the summit on 28 and 29 November, and during 1-3 December. Ashfall was reported in areas to the SW, W, NW, N, and NE on 28 November, and 3-4 December. Incandescent blocks rolled 500-1000 m down the flanks on 28 November, 1 December, and 3 December. Roaring noises were occasionally reported.
Sources: Instituto Geofísico-Escuela Politécnica Nacional – “Report provided courtesy of the Smithsonian’s Global Volcanism Program and the US Geological Survey’s Volcano Hazards Program.”