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Nevado del Ruiz

The Sleeping Lion of the Andes — Site of the Deadliest Lahar in History

Elevation

5,279 m

Last Eruption

2014–present

Type

Stratovolcano

Country

Colombia

Location

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Volcanic Hazards & Risk Assessment

Primary Hazards

  • Pyroclastic flows
  • Lava flows
  • Volcanic bombs and ballistics
  • Lahars and mudflows

Risk Level

Population at RiskLow
Infrastructure RiskHigh
Aviation RiskSignificant

Geological Composition & Structure

Rock Types

Primary
Unknown
Silica Content
Varied composition

Tectonic Setting

Unknown
Intraplate setting with hotspot or regional volcanic activity.

Age & Formation

Epoch
Unknown
Evidence
Unknown

Eruption Statistics & Analysis

MetricValueGlobal RankingSignificance
Total Recorded EruptionsUnknownLowModerately active volcano
Maximum VEIVEI UnknownMinorLocal impact potential
Recent Activity12 years agoRecentRecently active

Monitoring & Alert Status

Monitoring Networks

Global Volcanism Program
International eruption database

Current Status

Watch
Dormant but monitored. Capable of renewed activity.

Authority Sources

Smithsonian GVP
Official volcano database

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Volcano peak shrouded in dramatic clouds

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Interesting Facts

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The 1985 Armero lahar traveled 74 km from the summit at speeds exceeding 60 km/h, burying three-quarters of the town in just minutes.

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Nevado del Ruiz's 1985 eruption was only VEI 3 — a moderate event — yet it killed approximately 23,000 people, making it the fourth-deadliest volcanic disaster since 1500 CE.

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The volcano's ice cap has shrunk from approximately 25 km² in 1985 to roughly 10 km² in 2025, losing 60% of its glacial cover in just 40 years.

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Armero was built directly on lahar deposits from the 1595 and 1845 eruptions — the historical record of the hazard was literally beneath the town's foundations.

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Nevado del Ruiz is the northernmost glacier-bearing volcano in South America and one of only a handful of equatorial peaks with permanent ice.

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The Arenas Crater at the summit is 1 km wide and 240 m deep — large enough to fit approximately 200 football fields inside.

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A hazard map published in October 1985, just weeks before the disaster, correctly showed Armero within the lahar inundation zone, but evacuation orders were never effectively issued.

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The photograph of Omayra Sánchez, a 13-year-old trapped in Armero's debris for 60 hours before dying, won the 1986 World Press Photo of the Year.

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Colombia's volcano monitoring system was completely rebuilt after 1985, and the country now operates one of the most advanced lahar early warning networks in Latin America.

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At 5,279 m, Nevado del Ruiz stands higher than Mont Blanc (4,808 m) and any peak in the contiguous United States.

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The volcano lies at the heart of Colombia's Eje Cafetero (Coffee Axis), a UNESCO Cultural Landscape — its fertile volcanic soils produce some of the world's finest coffee.

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Between 1826 and 1833, Nevado del Ruiz erupted at least five times in rapid succession, an unusually active cluster that included four VEI 2 events.

Frequently Asked Questions

Is Nevado del Ruiz still active?
Yes, Nevado del Ruiz is an active stratovolcano that has been in a state of ongoing eruptive unrest since 2012. The Arenas Crater regularly emits ash plumes, volcanic gases (particularly sulfur dioxide), and generates volcanic earthquakes. The Colombian Geological Survey (SGC) continuously monitors the volcano with seismometers, GPS stations, gas sensors, and webcams. The volcano has been at elevated alert levels (Orange/Level III) multiple times in recent years. Volcanologists consider another significant eruption not a matter of if, but when.
What happened in the 1985 Nevado del Ruiz disaster?
On November 13, 1985, a VEI 3 eruption melted approximately 10% of the summit glacier, generating massive lahars (volcanic mudflows) that traveled up to 100 km down river valleys. The largest lahar descended the Lagunillas River and struck the town of Armero at approximately 11:30 PM, burying three-quarters of the town under 2–5 m of mud and debris. Approximately 23,000 people died, 5,000 were injured, and 5,000 homes were destroyed. It was the deadliest lahar event in recorded history and South America's worst volcanic disaster.
Could Nevado del Ruiz erupt again?
Yes, Nevado del Ruiz will almost certainly erupt again — it has been in a state of continuous low-level eruption since 2014. The volcano has produced 24 eruptions over the past 8,600 years, with at least four reaching VEI 4. While the shrinking glacier reduces the potential lahar volume somewhat, even the remaining ~10 km² of ice is sufficient to produce devastating mudflows. The SGC maintains detailed hazard maps and lahar early warning systems. The key difference from 1985 is that extensive monitoring and evacuation infrastructure is now in place.
How tall is Nevado del Ruiz?
Nevado del Ruiz stands 5,279 m (17,319 ft) above sea level, making it the northernmost glacier-capped volcano in South America. It is taller than Mont Blanc (4,808 m), the highest peak in the Alps, and taller than any mountain in the contiguous United States. The volcano's massive edifice covers more than 200 km², and its summit is capped by a diminishing ice field of approximately 10 km². The Arenas Crater at the summit sits at roughly 5,279 m with walls descending 240 m to the crater floor.
How many people died in the Armero tragedy?
Approximately 23,000 people died when lahars from the November 13, 1985 eruption of Nevado del Ruiz destroyed the town of Armero. An additional ~1,000 people were killed in Chinchiná by a separate lahar traveling down the Chinchiná River. Armero had a population of approximately 29,000, meaning roughly 75–80% of the town's inhabitants perished. The disaster also injured 5,000 people and destroyed 5,000 homes. It ranks as the deadliest lahar event in recorded history and the second-deadliest volcanic disaster of the 20th century, after the 1902 eruption of Mont Pelée.
What type of volcano is Nevado del Ruiz?
Nevado del Ruiz is a stratovolcano (composite volcano) built from alternating layers of andesitic lava flows, pyroclastic deposits, and volcanic debris. It was constructed over approximately two million years across three major building phases, with the modern cone occupying the caldera of an older collapsed edifice. The volcano is powered by the subduction of the Nazca Plate beneath the South American Plate. Its predominantly andesitic magma produces moderate explosive eruptions — typically VEI 2–4 — that are dangerous primarily because hot eruptive material melts the summit glacier, generating lethal lahars.
Can you visit Nevado del Ruiz?
Nevado del Ruiz lies within Los Nevados National Natural Park, which is open to visitors, but summit access is frequently restricted due to ongoing volcanic activity. When the alert level is at Yellow (Level III) or above, the upper mountain and crater area are closed to all climbers and trekkers. Lower elevations of the park offer excellent páramo hiking, hot springs (Termales del Ruiz), and views of the snow-capped peak. Access is typically from Manizales via 4x4 vehicle. Always check the SGC alert status before planning any visit to the upper mountain.
Why was Armero not evacuated before the 1985 eruption?
Despite over a year of volcanic warnings and a hazard map published weeks before the eruption that correctly identified Armero as at risk, the town was not effectively evacuated due to a combination of factors: conflicting government authority between local, regional, and national agencies; poor communication infrastructure (radio warnings were disrupted by the eruption itself); lack of public education about lahar hazards; economic pressures against evacuation; and a false sense of security from the volcano's long quiet period. The Armero tragedy became a global case study in disaster preparedness failure and led to sweeping reforms in volcanic risk management worldwide.