#EstemosListos: earthquakes and melting ice, the double risk of glaciers in Peru

At 3:23 pm on every May 31 there is silence in the region Ancash. The worst tragedy in its history, the worst in all of Peru for a earthquake, occurred in 1970. At that time, the 7.9 magnitude earthquake in front of Chimbote was registered, which in 10 minutes caused the detachment of a glacier on the northern peak of the Huascarán snow-capped mountain and an avalanche of 30 million tons of mud, ice and stones. . Of the city of Yungay, only 4 palm trees remained standing and barely 300 survivors out of a population of 25 thousand people. That day there were a total of 70,000 dead.

To the enormous dangers unleashed by large earthquakes, glacier detachment is added, and Áncash is the most exposed region. Global warming makes the situation even more critical.

The coordinator of the Glacier and Lagoon Assessment Area of ​​the National Water Authority (ANA), Alejo Cochachin, explains that in the last 50 years 53% of the country’s glacial surface has been lost. Although the increase in temperature has pushed them back towards the high areas of the snowy mountains, the location of the lagoons in Áncash puts the populations settled in the low areas at risk.

A sudden movement or a change in temperature can favor the detachment of huge blocks of ice adhering to the rock. Until 2019 there were 493 glaciers covering an area of ​​431 km2.

“In the history of the department of Áncash, more than 30 catastrophic events of glacial origin have occurred, in two scenarios the trigger was an earthquake ”, explains to this Journal. The first occurred in 1725 by an earthquake that produced an avalanche that buried 1,500 people and the avalanche of 1970.

Population at risk

Despite a history impacted by the behavior of glaciers, Cochachín warns that in recent years areas through which an eventual avalanche has been settled. “In Yungay a space was delimited that should not be occupied, but the population has once again begun to build houses in the lower part of the valley, which could directly be affected. The city grows in spaces that are not recommended”, dice.

In the case of Huaraz, capital of the region, it is estimated that 40 thousand people at risk from a possible discharge of the Palcacoch lagoona (at 4,560 masl). The increase in its volume due to global warming is a fact.

“Huaraz has been one of the populations that has grown in the alluvial cone. Palcacocha, due to glacial retreat, has increased its volume to more than 17 million cubic meters “, Explain. It is more than double the volume it had in 1941 (8 million cubic meters), when the detachment of a block from the snow-capped Palcaraju on the lagoon generated an avalanche that caused 1,800 deaths.

It’s not the only one. A report made by Indeci in July this year warned that there was “Imminent danger” of the Parón lagoon drainage, in the district of Caraz. If that happens, an avalanche would wipe out more than 22,000 people.

According to the National Institute for Glacier and Mountain Ecosystem Research (Inaigem), in an extreme scenario, an avalanche would be recorded from the glacier Hatunraju, which would directly impact the city of Caraz and nearby populated centers, causing in addition to human losses, economic damages for more than 300 million soles. Inaigem informed this newspaper that face-to-face socialization tasks with the population are scheduled for 2022.

Cochachín adds that a mechanism for preventing an event of this nature is the Early Warning System that allows the population to evacuate in time in the event of floods. For now, one has been implemented in lagoon 513. In Palcacocha there is another in the testing and calibration stage. For Cochachín, flood warning systems would be needed in at least 19 other lagoons.

The detachment of large blocks of ice is almost a matter of time with global warming, if an earthquake does not accelerate the process.

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