Activities  Cordillera Blanca

Geographical Situation

The Cordillera Blanca is located between 08° 30' - 10° 10' S, 77° 00' - 78° 00' W, in the Andean Department of Ancash, Peru, 400 km north of Lima.

A fragile and disputed area

The Cordillera Blanca covers an area 180 km long and 30 km wide in the Andean Department of Ancash, Peru. In 1975, a large part of its territory was established as the Huascarán National Park. It was internationally recognised as a Biosphere Reserve under UNESCO's Man and the Biosphere program in 1977 and inscribed on the World Heritage List in 1985.

Contrasting human activities take place within the park and its buffer zone: traditional agriculture and pastoralism, tourism and mountaineering, as well as mining development. These activities are potentially conflicting, for they compete for space and water resources, in a relatively harsh and fragile high-altitude environment, under the additional stress of severe natural hazards and changing climatic conditions.

Satellite imagery is a precious source of information on the temporal evolution of land cover, providing a timely inventory of key-parameters for resource management and habitability such as snow and ice cover, natural hazard occurrences and environmental impact of mining activities.

Glacial retreat

The Cordillera Blanca glacial cover has been slowly shrinking since the 70's. This decrease amounts to 15% over 25 years and is visible in the area of Pasto Ruri glacier. A continuing trend in global warming and/or precipitation imbalance could seriously decrease the water reserves stored as ice: this factor should be considered in water management strategies to be implemented in the region.


Ice and snow-capped Cordillera Blanca stretches over 180 km between Cordillera Negra (lower left) and the amazonian foothills (upper rigth). Vegetation surfaces show in green, recently deglaciated areas in white and bare rocks in pink. August 1996, Landsat 5 TM false colour composite (7,4,2)
The Pasto Ruri glacier between 1987 (left) and 1996 (right; yellow contours show 1987 situation).

Huge deadly avalanche

Andean glaciers have long been involved in numerous avalanches, which have caused considerable material losses and casualties by the thousands. The events of 1962 and 1970, originating from Huascarán northern summit, were particularly deadly: on May 31, 1970, a 7.7 magnitude earthquake triggered a huge avalanche, 25 km long and moving at 280 km/h, which wiped out the city of Yungay, claiming 18000 lives. The scars are still visible today.
Ice retreat induces the formation of numerous peri-glacial lakes, dammed only by fragile moraine deposits. Subject to erosion, these walls may collapse, triggering flash floods: another threat for local populations…


In 1970, a huge avalanche stormed down the slopes of Mount Huascarán North. It devastated a 25 km long strip of the valley (in red), wiping out the cities of Ranrahirca and Yungay and killing 18000 people.

1962

1970
Almost nothing remains of Yungay city, literally erased by the 1970 avalanche.

1989
The twin peaks of Huascarán loom over the scars of the 1970 avalanche, still visible in 1989.

Mines are growing

Recently, two large mining projects were developed in the vicinity of the National park. Population increased, and so did the needs for water and electricity, not to mention the construction of infrastructures. The impact on the environment is visible and serious: dumping of mine residues, using the lakes for hydro-electric production, diverting mountain streams for water supply. In the power struggle that follows, what are the chances of the local farmers to get a fair share of the resources?


Wastes from seventies and eighties mining activity in Callejón de Huaylas Valley.

1996

2000
The impact of Antamina mine on the pristine landscape is clearly visible: shrinking of the lake, ore and rock dumps, constructions and roads.

 

What future?

A beautiful, still largely pristine region with endemic plants and animal attracting a growing number of tourists, a wealth of mineral resources not fully developed yet, a geologically active, dangerous environment, and an indigenous population with rights to live off, and on their land: these are the elements to consider when attempting to manage the territory in the Cordillera Blanca, accounting in addition for the observed climatic trend in glaciers retreat… quite a formidable challenge!

 


Poster Quick Look

Research conducted by: Walter Silverio, University of Geneva