OVSICORI-UNA reported that on 20 April a dense water vapor plume rose from a vent in the newly-forming pyroclastic cone at the site of the old dome in the hot lake at Poás.
Gas flux increased from 1,000 tons/day (t/d) on 13 April to 2,500 t/d on 20 April.
During 20-22 April Strombolian activity ejected tephra that fell around the vent within a 300-m radius.
Gas-and-ash plumes rose 200 m above the vent.
The Red Cross of Grecia reported ashfall in Alajuela, Fraijanes, San Miguel, Carbonal, Cajón, San Francisco, San Roque, and San Juan Norte de Poás.
Events at 1316 and 1603 on 22 April produced plumes of unknown height.
Several more eruptive events were recorded that day; an event at 2212 was very intense, ejecting bombs large distances.
An event at 1215 on 23 April generated a plume of unknown height.
Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)