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The arid Atacama Desert in Northern Chile is one of the driest places on Earth, with some areas receiving just 0.5 millimeters of rain per year. That extremely dry weather has made the Atacama a prime site for stargazing, and the desert is home to some of the most powerful telescopes we have at our disposal. But a recent freak snowstorm dusted the desert with flakes and sent one of these scopes into shutdown.
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Why The Atacama Desert Is The World’s Driest Place
Shielded from passing moisture by its position near the equator, proximity to cold ocean currents in the nearby Pacific, and the influence of the nearby Andes mountains, the Atacama has been dry for millions of years.
The desert spans roughly 40,000 square miles. One region of the desert, the Altiplano plateau, is about 13,123 feet (4,000 meters) above sea level and is one of the sunniest places on Earth, according to a study in the Bulletin of the American Meteorological Society.
Snow in the Atacama Desert
On the even higher Chajnantor plateau, in an area of the desert with extraterrestrial landscape, sits a cluster of space telescopes, including the Atacama Large Millimeter/submillimeter Array (ALMA) observatory. ALMA is made up of 66 antenna dishes that pick up scarce energy signals from the far corners of space. The lack of atmospheric interference in the Atacama makes it easier for ALMA to pick up these signals.
In June 2025, ALMA was caught in a highly unusual snowstorm, forcing it to enter an emergency “survival mode.” ALMA’s research team repositioned her dishes, tilting them to prevent snow buildup. This temporarily halted the telescopes’ observations. The storm was localized, so the Southern Astrophysical Research (SOAR) Telescope and the Vera C. Rubin Observatory, both sited in the Atacama but just a few hundred miles southwest of ALMA, were not affected.
The intense solar radiation that bathes the Atacama removes snow quickly, and the latest dusting had mostly disappeared within a month. It’s likely that some of this snow was not melted but instead converted directly into a gas through a process called sublimation. This process is driven by the intensity of local sunlight and the aridity of the atmosphere, according to NASA Earth Observatory.
A Wetter Future In The Atacama?
The Atacama’s incredibly dry climate may be subtly shifting. The region recorded no rainfall between October 1903 and January 1918, but snow fell in 2011, 2013, and 2021. The desert may appear lifeless, but hardy microbes and plants hide beneath the ground. Unseasonal desert rains, which occurred just last year, can cause the dry, cracked desert surface to bloom with intense color as desert flowers emerge months early.
The changing climate in the region has had negative impacts as well. In March 2015, heavy rain in a region where such weather is almost alien caused a series of deadly floods. In the coastal city of Chañaral, which borders the desert, the Salado River hit a maximum depth of about 14.76 feet (4.5 meters). The flooding caused widespread damage to homes, roads, and bridges, and 31 people died.
These recent cases of climate change in the region may be further examples of how the anthropogenic climate crisis is altering the planet. Soon, snow in the desert may become a more common challenge for ALMA to reckon with.
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Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
This article references information from a study published in the Bulletin of the American Meteorological Society: Surface Solar Extremes in the Most Irradiated Region on Earth, Altiplano
This article references information from the Atacama Large Millimeter/submillimeter Array: About ALMA, at first glance
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