Andes Mountains
Photo: Pixabay
One of the main topics of conversation in recent days has been the accident of the Uruguayan Air Force plane that had 45 people on board, including five crew members and members of a rugby team. The crash occurred on October 13, 1972 on a mountain in the Andes, which, at nine thousand kilometers long, is one of the longest mountain ranges in the world.
This accident, also known as the “Miracle of the Andes,” has gained prominence with the recent film “Snow Society,” which tells the story of the 45 passengers, including 16, who survived 72 days in the Andes. in extreme conditions, such as those who died.
“The Snow Society” is based on the 1972 plane crash in which a rugby team from Uruguay was traveling to Chile. / Netflix
According to records at the time and survivors' statements, the Uruguayan plane crashed at 3,500 meters above sea level because it was flying at low altitude. As a result, the plane lost its wings and tail and, due to the violence, slid through the snow for about two and a half kilometers until it braked in the Valley of Tears in Mendoza (Argentina).
The aircraft ultimately remained on the surface without destruction. However, more than 50 years later, the Andes have changed. A study conducted by the Antarctic Research Group of the Faculty of Physics at the University of Santiago de Chile and published in the journal Nature in 2019 detailed this transformation.
Scientists analyzed images between 1986 and 2018 to study snow cover during the dry season in a region from 18° south latitude to 40° south latitude. They used more than 400 images for each of the three macrozones in the period 1986–2005 and 200 images for the period 2006–2015.
Researchers say snow is very sensitive to drastic changes such as an increase in temperature or a decrease in precipitation. The study shows that the annual amount of snow has steadily decreased at these latitudes between 10% and 20% per decade. For this research, scientists relied on images captured by satellites. They then compared the snow cover recorded by the satellite in May 2018 with all May months of the last 20 years.
Specifically, snow is decreasing by about 16% per decade in tropical areas, 10% in colder areas and -15% in central areas. In tropical and cold regions, snow losses are mainly attributed to changes in El Niño, which have decreased in intensity.
This decline in snow cover was particularly “significant” in the Southern Hemisphere, affecting areas in west-central Argentina and central Chile. The decline in snowpack has been attributed to rising temperatures and, to a greater extent, changing rainfall patterns. Large-scale climate phenomena such as the El Niño-Southern Oscillation (ENSO) and the Southern Annular Mode (SAM) influenced interannual variability and impacted snow amounts.
El Niño is a climate phenomenon that occurs in the Pacific Ocean. During El Niño, sea water near the equator becomes warmer than normal. The Southern Oscillation (El Niño Southern Oscillation, ENSO), in turn, is a climate pattern that is related to El Niño. ENSO is changes in sea surface temperatures and air pressure in the equatorial Pacific.
Finally, the so-called “Southern Annular Mode” or SAM is a climate pattern that primarily affects Antarctica and surrounding regions. It refers to changes in the position and intensity of westerly winds around Antarctica. When the SAM is in its positive phase, westerly winds tend to be more concentrated around the South Pole.
So the study suggests that there will be less precipitation as the Niño-Southern Oscillation (ENSO) weakens and westerly winds shift poleward along with a Southern Annular Mode (SAM). This decrease in precipitation results in less snow in the region. That means climate factors like these lead to less rain and, as a result, the amount of snow falling, the study says.
“We have already lost 1/3 of the snow cover in the last 30 years (…) and it is unlikely that we will regain it because we would have to recover precipitation and that is difficult because of the whole climate “Models suggest that we will continue to lose rainfall to varying degrees until the middle of the century,” lead author Raúl R. Cordero added to Ágora. It should not be forgotten that the snow in the Andes is crucial to the water supply in various parts of South America.
For example, streams carry meltwater to populated areas in west-central Argentina and central Chile, where it is important for urban water supplies, power generation, and agriculture. Although it is unclear whether snow losses will continue in the future, climate change could increase the variability of snow amounts.
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