The alert level of the Rincon de la Vieja volcano in Costa Rica has been raised due to an “eruptive process in progress” caused by multiple phreatic eruptions that occurred in May. The volcano has gone from yellow alert level “warning” (2 out of 4) to orange alert level “caution” (3 out of 4) after several continuous eruptions in recent weeks, some of which have produced columns of water vapor and volcanic material that have reached heights of more than 3,000 meters above the crater level, according to reports from official agencies.
The Rincón de la Vieja volcano, located in the Guanacaste region, about 270 km northwest of San José, is currently the most active volcano in Costa Rica. The change in the alert level is due to an increase in eruptive events, which totaled 58 in May alone. This implies the possibility of explosions or eruptions, ash or lava emissions, pyroclastic flows of “small extension,” or a significant increase in seismic activity, among other factors, according to the Vulcanological and Seismological Observatory of Costa Rica (OVSICORI) of the National University (UNA).
So far, the volcano has experienced phreatic eruptions every several days, which occur when hot magma interacts with water, vaporizes, and increases its volume in seconds, generating an explosion. According to the National Emergency Commission (CNE), the main danger lies in the lahars, a mixture of mud and hot water that travels down the slopes and rivers of the volcano and could reach populated areas.
Although there are currently no populations near the volcano that could be affected, the CNE activated the “informative” green alert level (1 of 4) a week ago for the communities closest to the massif in order to activate the communal emergency committees and maintain constant communication between the populations, authorities, and scientists.
According to the CNE, Rincón de la Vieja is in a “peak of activity” in the middle of an eruptive phase that began in November 2022. The volcano, which is located within the National Park of the same name, is a 1,895-meter-high massif located in the Central Mountain Range of Costa Rica, which crosses the center of the country from north to south.