RVO reported that during 13-15 May gas plumes from Rabaul caldera’s Tavurvur cone produced a haze to the W and NE. During 15-21 May, ash plumes rose to altitudes of 1.7-2.7 km (5,600-8,900 ft) a.s.l. and drifted NE, N, and NW. Ashfall was reported in areas downwind, including Rabaul Town (3-5 km NW). Occasional roaring noises and incandescence at the base of the plume was noted.
Source: Steve Saunders and Herman Patia, Rabaul Volcano Observatory (RVO) – “Reports provided courtesy of the Smithsonian’s Global Volcanism Program and the US Geological Survey’s Volcano Hazards Program.”