Poás Volcano erupted twice on Sunday, producing a plume that rose 300 meters above the crater, according to the Volcanological and Seismological Observatory (OVSICORI). The activity, classified as a moderate phreatomagmatic eruption, prompted authorities to close Poás Volcano National Park until further notice. OVSICORI reported that the eruptions followed a pattern of heightened activity observed over recent weeks.
The volcano has been under close watch since small eruptions began in January, with a notable increase recorded this month. On March 1, a plume reached 400 meters, and Sunday’s events marked the most significant activity of the year so far. Maarten de Moor, an OVSICORI volcanologist, confirmed that the alert level was raised from warning (Level 2) to caution (Level 3) on Friday due to escalating seismic activity, gas emissions, and structural changes in the volcano. “We’ve seen a steady climb in activity since late 2024,” de Moor said. “This suggests the potential for larger eruptions in the coming hours or days.”
Unlike last year, when eruptions were confined to the C-mouth vent, current activity involves multiple crater points and signs of increased magmatic input. OVSICORI noted elevated sulfur dioxide levels, with reports of sulfur odors reaching Sarchí and Alajuela over the weekend. No ashfall was confirmed on Sunday, though monitoring continues. De Moor explained that the phreatomagmatic nature of the eruptions—caused by steam and magma interaction—indicates a shift from 2024’s predominantly water-driven events.
The National System of Conservation Areas (SINAC) and OVSICORI reinstated visitor restrictions following the eruptions, closing the park Sunday afternoon. Earlier this year, the park operated with limited capacity—56 visitors per shift—before briefly returning to normal in February. “The situation requires constant oversight,” SINAC stated. “We urge residents and tourists to stay informed as further eruptions are possible.”
Here’s how this year’s activity compares to last:
| Aspect | 2024 Activity | 2025 Activity (March 9) |
|---|---|---|
| Eruption Type | Mostly phreatic | Phreatomagmatic |
| Active Area | C-mouth vent | Multiple crater zones |
| Alert Level | Warning (Level 2) | Caution (Level 3) |
| Park Status | Open with restrictions | Temporarily closed |
Authorities reported no immediate threats to nearby communities, though sulfur gas remains a concern. OVSICORI and SINAC will provide updates as the situation develops. Residents and visitors are advised to monitor official channels for the latest on Poás Volcano’s activity.
