Rare snowfall in the driest locations on the planet has halted the operation of one of the world’s leading telescope arrays. Climate change can mean that stations will face such extreme weather events in the future.
Snow has less than an inch of rainfall per year, with Atacama’s large millimeter/sub-millimeter array (ALMA), a large network of radio telescopes in northern Chile, at the home.
Snowfall occurred at Alma’s operational support facility, located at an altitude of approximately 9,500 feet (2,900 meters) north of Santiago, about 1,050 miles (1,700 kilometers). Scientific operations have been suspended since Thursday (June 26th).
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“We’ve had no snow record at base camp for over 10 years. There’s no snow every day in Alma!” an Alma representative told Live Science via WhatsApp.
Alma’s radio telescope array is perched in the Chaginant Plateau, a 16,800-foot (5,104 m) desert plain in Chile’s Antofagasta region. Typically, three snowfalls are seen per year. The plateau, shared by Chile, Bolivia and Peru, usually experiences blizzards during two seasons. And from June to July, during the winters of the Southern Hemisphere, said Raul Coldero, a climatologist at the University of Santiago.
“In winter, some storms are fueled by moisture from the Pacific Ocean, which can extend rainfall to the coastal regions of the Atacama Desert,” Cordero told Live Science. At elevations above 16,400 feet (5,000 m), annual snowfall ranges from 8 to 31 inches (20 to 80 cm).
However, the 3,000 metres (9,840 feet) of snowfall at Alma’s base camp is “a lot less often,” Cordero noted.
This week’s snowfall was caused by unusual atmospheric instability affecting North Chile. Chilean Weather Service has issued snow and wind warnings due to the passage of “cold cores” through the area, meteorologist Elio Brufort said. “We issued wind warnings to the Antofagasta area and further north, with gusts reaching 80-100 km/h. [50-62 mph]”Blue Fort told the local media.
This phenomenon was accompanied by heavy rain further north, causing the stream to swell and damage some properties. Schools were ordered to close, with blackouts and landslides reported. So far, no victims have been reported. Weather events of this scale have not been seen in nearly a decade.
Extreme conditions paralyze Alma
As of Friday, Alma reported to Live Science that the snowstorm remained active against the Chaginantor Plateau, so scientific work continued to be stopped to protect the antennas from extreme weather conditions. Early on Thursday morning, the observation deck activated its “survival mode” safety protocol. In addition to snowfall, temperatures plummeted to 10 degrees Fahrenheit (12 degrees Celsius).
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As part of this protocol, all Alma’s large antennas are redirected downwind, helping to minimize potential damage from snow accumulation and gusts of wind.
“As the storm passes, the snow-closing team will be active immediately and visually inspect each antenna before resuming observation,” said an Alma representative. “This should occur quickly as some of the best observation conditions occur right after snowfall. Coldness reduces the humidity of the air, which is the most hampering the readings.”
Consisting of 66 precision antennas spread across the Chagenant Plateau, Alma is an international collaboration that forms the most powerful radio telescope on the planet, designed to handle such extreme weather phenomena.
The fact that the snow has stopped raises questions about the operation of the array as the weather warms.
The Atacama Desert usually receives only 0.04-0.6 inches (1-15 mm) of precipitation per year. Many areas can go for years without recording measurable rain or snow.
Are these events more frequent? “That’s a good question,” replied Cordero.
“It’s still too early to link low-altitude snowfalls in the desert directly to climate change, but climate models predict potential increases in precipitation, even in this overheated area,” he concluded. “We can’t say for certain whether that increase is already underway.”
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