Nevados

The term “Nevados” (Spanish for snow-covered or snowy mountains) refers to high volcanic or non-volcanic mountain peaks in the Andes and other high-altitude regions of South America that are perennially or seasonally capped with snow or glaciers. The word is commonly used in the Andean countries—notably Chile, Peru, Bolivia, Colombia, Ecuador, and Argentina—to denote lofty summits that remain snow-clad due to their elevation and climatic conditions.
Nevados are among the most prominent geographical and geological features of the Andean mountain system, many of which are active or dormant volcanoes forming part of the Pacific Ring of Fire. These peaks are of immense scientific, environmental, and cultural importance.

Meaning and Etymology

• The word “Nevado” comes from the Spanish verb nevar, meaning “to snow.”
• In geographical usage, it describes mountains covered with snow or ice, regardless of whether the snow cover is permanent or seasonal.
• The plural form “Nevados” is often used to refer to groups of snow-covered volcanoes or peaks (e.g., Los Nevados).

Thus, a Nevado can be understood as a snow-clad Andean mountain or volcano, usually rising above 4,500–6,000 metres in elevation.

Geographic Distribution

Nevados are widely distributed across the Andes Mountains, which stretch for about 7,000 kilometres along the western edge of South America. The major countries hosting Nevados include:

1. Chile:
   • Home to numerous volcanic Nevados along the Andean Volcanic Belt.
   • Examples: Nevado Ojos del Salado (6,893 m – the world’s highest active volcano), Nevados de Chillán, Nevado de Tres Cruces, Nevado San Pedro.
2. Argentina:
   • The Andes of Argentina include high, glaciated volcanic peaks.
   • Examples: Nevado de Cachi, Nevado de Famatina, Nevado de Chuscha, and Nevado de los Andes.
3. Peru:
   • Peru’s Cordilleras contain numerous Nevados forming part of the Cordillera Blanca and Cordillera Vilcanota.
   • Examples: Nevado Huascarán (6,768 m – Peru’s highest peak), Nevado Alpamayo, Nevado Ausangate, Nevado Salcantay.
4. Bolivia:
   • Contains several snow-covered volcanic and non-volcanic summits in the Cordillera Real and Altiplano.
   • Examples: Nevado Sajama (6,542 m – Bolivia’s highest peak), Nevado Illimani, Nevado Huayna Potosí.
5. Ecuador:
   • Situated near the equator yet supporting snow-clad volcanoes due to high altitude.
   • Examples: Nevado Chimborazo (6,263 m – Earth’s closest point to the sun), Nevado Cotopaxi (active volcano), Nevado Cayambe.
6. Colombia:
   • Contains isolated Nevados in the Central and Eastern Cordilleras.
   • Examples: Nevado del Ruiz (active volcano), Nevado del Tolima, Nevado del Huila, Nevado Santa Isabel.

These Nevados form part of the Andean Volcanic Arc, a product of subduction zones where the Nazca and Antarctic Plates slide beneath the South American Plate.

Geological Nature

Most Nevados are volcanic in origin, formed through successive eruptions and the accumulation of lava, ash, and pyroclastic material. However, some are non-volcanic, consisting of metamorphic or granitic rocks uplifted by tectonic forces.
Key geological features:

• Volcanic Structure: Many Nevados exhibit stratovolcano morphology—tall, conical peaks built from alternating layers of lava and ash.
• Glaciation: Permanent or semi-permanent glaciers and snowfields crown the summits, especially above 5,000 metres.
• Seismic Activity: Several Nevados remain active, producing fumaroles, earthquakes, and eruptions (e.g., Nevado del Ruiz in 1985).

Climatic Conditions

The presence of snow and glaciers on Nevados depends on altitude, latitude, and climatic factors:

• Snow Line Variation:
  • Near the equator, permanent snow occurs above 4,800–5,000 m.
  • In temperate latitudes of Chile and Argentina, it descends to about 3,000 m.
• Temperature:
  • Mean annual temperatures near the summits remain below 0°C.
• Precipitation:
  • High-altitude moisture from the Pacific Ocean and Amazon Basin contributes to snowfall and glacial formation.

However, climate change and global warming have caused significant glacial retreat across many Nevados, reducing snow cover and altering water resources downstream.

Hydrological and Ecological Importance

Nevados play a critical role in the hydrology and ecology of the Andes:

1. Water Source:
   • Glaciers and snowfields act as natural reservoirs, releasing meltwater gradually into rivers and valleys.
   • They feed major South American rivers such as the Amazon, Orinoco, and Paraná through Andean tributaries.
2. Irrigation and Agriculture:
   • Meltwater supports highland agriculture, sustaining crops and livestock in arid Andean regions.
3. Ecosystems:
   • The lower slopes host puna and páramo ecosystems, rich in endemic flora and fauna adapted to cold, high-altitude environments.
4. Climate Regulation:
   • Snow and ice reflect solar radiation (high albedo effect), influencing regional climate patterns.

Cultural and Historical Significance

Nevados hold deep spiritual and cultural significance for the indigenous peoples of the Andes, including the Quechua and Aymara communities.

• In Inca mythology, snow-capped peaks were considered sacred deities or “apus”, protectors of the people and sources of fertility.
• Ritual offerings (apachetas or pagos a la tierra) are still made on mountain slopes to honour these spirits and ensure good harvests.
• Nevados also serve as landmarks in Andean cosmology and navigation.

Additionally, many Nevados are associated with historical exploration, mountaineering, and scientific research, serving as natural observatories for studying climate and glaciology.

Notable Nevados

(Note: The term “Nevado” is also used for high volcanic peaks in Mexico, such as Nevado de Toluca and Nevado de Colima, extending its use beyond South America.)

Environmental Concerns

Modern studies show that many Nevados are undergoing rapid deglaciation due to global warming:

• Glaciers in the Cordillera Blanca (Peru) have lost nearly 30–40% of their mass since the mid-20th century.
• Reduced meltwater threatens water supply, hydropower generation, and agricultural systems downstream.
• The loss of glacial mass increases the risk of glacial lake outburst floods (GLOFs).