The volcano showed a dramatic activity at 16:18 local time on 2 May.
A strong eruption culminated in a pumice-and-ash flow caused by an ash plume collapse. The pyroclastic flow raced down through the southwestern Ceniza gorge. Phoenix clouds, typical phenomena for pyroclastic flows, appeared to happen as billowing grey ash plumes separated from the torrent. Plumes reached approx. 16,400 ft (5,000 m) and extended about 40 km to the west-southwest of the volcano.
The reason for this flow was likely the accumulation of denser pyroclastic material in the ash column and its partial destabilization due to gravity. Pyroclastic flows are deadly, turbulent hot avalanche of lava rock fragments of all sizes embedded in a mixture of turbulent gas and ash racing down slopes.
Source: Instituto Nacional de Sismología, Vulcanología, Meteorología e Hidrología volcano activity update 4 May 2023
