ACTIVE VOLCANO
Pacaya's Eruption History, From 1965 to Today
Pacaya has erupted almost continuously since the 1960s, including a violent 2010 blast and a 2021 lava episode — the history, and why hikes still stay safe.
See Pacaya Volcano hikes on GetYourGuide ↗Waking up in 1965
Pacaya had been quiet for a long period before it reawakened in 1965, building the cone now known as the MacKenney cone inside the collapsed rim of an older, larger volcano. From that year until 2010, Pacaya was in a state of nearly continuous eruption — 45 years of intermittent lava fountaining, ash emissions and small flows that steadily reshaped the mountain's upper slopes. That long active phase is part of why Pacaya is usually ranked among the most active volcanoes in Central America, and why the lava fields hikers walk through today are geologically young rather than ancient.
The 2010 eruption
On 27 May 2010, Pacaya produced a violent eruption with lava fountains reported around a kilometre high and an ash plume that drifted toward Guatemala City. The capital's international airport closed for several days as ash coated the runway, and the eruption caused several fatalities, including people who had approached too close to the active vent. The event struck within days of Tropical Storm Agatha, and the combination significantly complicated the emergency response. It remains the eruption most associated with Pacaya in the public record, and a reference point for how quickly conditions on an active volcano can change.
2021 — lava on the flanks
A more recent bout of heightened activity ran from roughly February to May 2021, with lava flows breaking out from fissures on Pacaya's northwest, west, south and north flanks. One flow travelled more than two kilometres down the mountainside, and the molten rock damaged coffee and avocado plantations on the lower slopes near the volcano's base. Unlike 2010, this episode was largely effusive — flowing lava rather than explosive fountaining — which is typical of much of Pacaya's activity, even if it's less dramatic in the headlines than a violent blast.
Why the accessible route isn't fixed
Because Pacaya keeps producing new lava and periodically closes off old paths, there's no single, permanent hiking trail to a fixed crater edge the way there might be on a dormant mountain. The route guides use, and how close hikers get to the MacKenney cone, is reassessed as conditions change — sometimes rerouted around a fresh flow, sometimes pulled back further from the vent during periods of stronger activity. That's a safety decision, not an inconsistency in the product: a hike that reaches the crater rim on one visit and stops well short on another is Pacaya behaving normally, not a tour falling short of expectations.
Eruption timeline at a glance
Pacaya's modern activity spans six decades, moving between quiet stretches, small lava flows and the occasional violent event, so it's easy to lose track of what happened when. This is a simplified timeline of the episodes most relevant to what hikers see and hear about today, from the volcano's reawakening in the 1960s through its two best-documented modern eruptions — not a complete volcanological record, but enough to understand why the mountain's lava fields look as young as they do, and why guides and park authorities keep adjusting exactly how close hikers can get to the active cone.
Pacaya eruption timeline
| Year / period | What happened |
|---|---|
| 1965 | Pacaya reawakens after a long dormancy; the MacKenney cone begins forming |
| 1965–2010 | Nearly continuous mild-to-moderate activity — one of Central America's longest active phases |
| 27 May 2010 | Violent lava fountaining and ash fall; Guatemala City's airport closes for several days |
| Feb–May 2021 | Largely effusive eruption; lava flows travel more than 2km down several flanks |
| Ongoing | Periodic minor activity continues; access is managed day to day by park authorities and guides |