A winter storm in August 2026 swept across the Atacama Desert in Chile, blanketing vast stretches of one of the driest places on Earth in snow and pushing near the Pacific coastline, according to satellite imagery and local reports. The unusual weather event, captured by NASA’s Landsat 8 and Landsat 9 satellites on August 6 and 14, followed a previous major event in July that impacted the Norte Chico region, demonstrating how shifting global atmospheric patterns can deliver dramatic precipitation to hyper-arid terrain.
Satellite Data Reveals Widespread Snow in Atacama Desert
The winter storm moved from the Andes Mountains, crossing the central desert floor before reaching near the coast. While minor snow events occurred in Atacama in 2011 and 2025, the reach of the August 2026 storm was unusual, turning brown and barren landscapes into expanses of white captured by NASA’s orbital imaging systems.
Did you know? Satellites like Landsat 8 and 9 use advanced remote sensing technology to track dramatic environmental shifts, allowing scientists to monitor rare weather events in remote global deserts in real time.
Extreme Rainfall Triggers Flash Floods and Mudflows
Snow was not the only byproduct of the atmospheric system. Heavy downpours triggered flash floods and mudflows across parts of northern Chile where infrastructure remains unequipped for large volumes of water. In Taltal, roughly 40 millimeters of rain fell over a three-day period.
That total represents about 10 times the city’s average annual precipitation, according to René Garreaud, an atmospheric scientist at the University of Chile. Garreaud noted in statements to Science Daily that such occurrences happen only a few times per decade, meaning a single storm delivered a decade’s worth of typical rainfall in a matter of days. Chilean authorities reported that thousands of residents were affected and hundreds of homes sustained heavy damage.
Atmospheric Triggers and the Role of El Niño
The system was driven by an atmospheric configuration known as a cutoff low, which split from the jet stream and funneled moisture into the region. This low-pressure trough tapped into coastal moisture supplies, clashing with the typical barriers that keep Atacama dry—namely the Andes Mountains, the cold Humboldt current, and regional atmospheric systems.
Scientists examining the broader climate context pointed to an intensifying El Niño. According to researchers, El Niño weakens the subtropical high-pressure system over the Pacific that normally maintains arid conditions, allowing southern storm tracks to shift closer to Chile’s subtropical zones and drive severe weather deep into the desert.
Impact on Major Astronomical Observatories
High-altitude scientific installations felt the direct effects of the storm. The severe winds and thick snow forced operations to halt at the Atacama Large Millimeter/submillimeter Array (ALMA), situated on the Chajnantor plateau. Observatory staff engaged special protection modes for the radio antennas, while other coastal and high-desert astronomical facilities similarly suspended operations until the storm cleared.
Frequently Asked Questions
Why is the Atacama Desert normally so dry?
The region’s extreme aridity is caused by a combination of the towering Andes Mountains, the cold Humboldt current offshore, and persistent atmospheric pressure systems.
How much rain fell during the August 2026 storm?
In Taltal, northern Chile, nearly 40 millimeters of rain fell over three days, equating to roughly 10 times the city’s usual annual rainfall total, according to University of Chile atmospheric scientist René Garreaud.
Did the storm disrupt scientific research in the region?
Yes. Heavy snow and high winds forced major facilities, including the ALMA observatory on the Chajnantor plateau, to temporarily halt operations and secure their equipment.
What caused the rare weather pattern?
A cutoff low-pressure system combined with an intensifying El Niño event, which weakened the Pacific subtropical high-pressure zone and shifted storm tracks toward the hyper-arid desert.
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