The IG reported that during 4-8 February visual observations of Tungurahua were limited due to cloud cover; steam-and-ash plumes rose 0.5-1 km above the summit during 7 and 9-10 February. Plumes drifted W and NW. Cannon shots, roaring noises, and sounds resembling blocks rolling down the flanks were seldom reported. Based on pilot observations, the Washington VAAC reported that an ash plume rose to an altitude of 8.5 km (28,000 ft) a.s.l. and drifted SSE. On 4 and 8 February IG reported that ash fell in areas to the SW. Incandescence from the crater was seen at night on 6 February.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG); Washington Volcanic Ash Advisory Center (VAAC) – “Reports provided courtesy of the Smithsonian’s Global Volcanism Program and the US Geological Survey’s Volcano Hazards Program.”