Unexpected snow hits Atacama Desert, forces World’s Largest Radio Telescope to pause

In July, large parts of the region of Atacama Desert experienced a thick dusting of snow. (Image: NASA//Landsat 9)

• Rare snowfall blanketed Chile's Atacama Desert in July 2025, stunning scientists
• Snow disrupted observatories like ALMA, forcing them to pause operations.
• Researchers are studying climate links to this once-in-a-lifetime weather event.

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The Atacama Desert is famous for being one of the driest regions on Earth, with some areas receiving almost no measurable rainfall for decades. Yet in July 2025, the desert appeared to turn white overnight, leaving scientists and locals astonished.

This extraordinary sight was captured by satellite images, showing snow dusting the normally barren landscapes, including the high-altitude Chajnantor Plateau. The event temporarily disrupted operations at some of the world’s most advanced observatories.

What Exactly Happened in the Desert?

A rare cold-core cyclone passed through northern Chile, depositing snow across parts of the Atacama Desert. The snowfall affected the Atacama Large Millimeter/submillimeter Array (ALMA) and other observatories. ALMA entered “survival mode”, pausing observations and repositioning antennas to avoid damage from the snow.

Who Observed and Recorded This Rare Event?

The snowfall and its impacts were captured by NASA’s Landsat 9 satellite. Field scientists from the Atacama Desert Research Institute also documented conditions on the ground. Observations focused on the Chajnantor Plateau, home to ALMA and several other high-altitude observatories.

What Surprised Scientists About This Event?

The researchers noticed that even light, short-lived snow disrupted scientific equipment temporarily. It created an unusual visual contrast, covering the desert’s normally barren terrain in bright white snow. Scientists were amazed that small precipitation events could affect such a dry and extreme ecosystem.

Is Snow in the Atacama Really That Rare?

Yes, the snow in the Atacama Desert is extremely rare, especially in areas that have been dry for decades. Scientists emphasise that such events are exceptionally uncommon, making this a once-in-a-lifetime observation. It highlights how climate variability can bring extreme weather to even the driest regions.

Are Further Studies Being Conducted on This Phenomenon?

Following the snow, scientists are investigating links to climate change and atmospheric conditions that triggered it. Research includes satellite imagery analysis, field surveys, and climate modelling to understand rare precipitation events. The findings will help improve predictions of unusual weather and guide observatory planning in extreme environments.