A series of winter storms affected northern Chile during August 2026, delivering snow to parts of the Atacama Desert, one of Earth’s driest regions. While snowfall in this area is not unheard of, having occurred in previous years such as 2025 and 2011, the scope and reach of the August storms were noteworthy. Satellite imagery from NASA’s Landsat 8 and Landsat 9 satellites, collected on August 6 and August 14, documented the dramatic transformation across the landscape. The Chajnantor plateau, which sits at high elevation within the Altiplano-Puna volcanic complex and hosts the ALMA radio telescope facility, experienced heavy snow and strong winds that forced the observatory to suspend operations and move its antennas into protective mode.
Later in the month, a second storm system produced even more extensive snow coverage, spreading westward from the Andes across the hyperarid core of the Atacama toward the Pacific coast near Antofagasta. Multiple major astronomical facilities in the coastal region halted operations during the weather event. According to René Garreaud, an atmospheric scientist at the University of Chile, the late August storm developed under unusual circumstances involving a large atmospheric trough that separated from the jet stream and extended across much of the Southern Hemisphere. Combined with abundant moisture from coastal sources, this disrupted pattern generated precipitation across an exceptionally wide geographic area, with rain and snow falling from offshore regions through the desert and over the mountain range.
The precipitation totals reached levels rarely documented in the otherwise extremely arid region. In some coastal areas, the rain fell at extraordinary intensity—the city of Taltal received approximately 40 millimeters of rainfall over three days, representing roughly ten times its average annual precipitation. The intense weather triggered mudflows and flash flooding across northern Chile, affecting thousands of people and causing significant damage to hundreds of homes, according to reports from the National Disaster Prevention and Response Service.
Atmospheric scientists attributed the unusual winter pattern to multiple factors, including a strengthening El Niño phenomenon. During El Niño conditions, the subtropical Pacific high-pressure system that typically maintains dry conditions over the region weakens, while a blocking high develops over the South Pacific. These changes shift the Southern Hemisphere storm track closer to the equator, enabling powerful weather systems to penetrate areas normally shielded from precipitation. Garreaud noted that such intense precipitation events occur rarely, appearing only a few times per decade or less in this region.
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