A school of fish-shaped clouds hovered above the glacial lake in Patagonia on December 27, 2025, as captured by an astronaut on board the International Space Station. The photograph sparked debate among NASA scientists and researchers about the type and origin of these unusual clouds.
"We can't identify them just from this one image," said Maria Hakuba, a research scientist at NASA's Jet Propulsion Laboratory. "The lens shape reminds me of lenticular clouds, which usually form near or over mountains." Lenticular clouds are created when prevailing winds are forced up and over a topographic barrier, often a mountain range.
Hazem Mahmoud, an atmospheric science lead at NASA's Langley Research Center, offered further insight into the phenomenon. MODIS data suggest cloud-top altitudes near 9,200 meters (30,000 feet) and cloud-top temperatures around 220 Kelvin, along with relatively large particle sizes consistent with the presence of ice crystals.
"It looks like we have a Cirrocumulus lenticularis," Mahmoud said. "Strong surface-level winds common in Patagonia likely swept across the glacial lakes of Los Glaciares National Park, forcing unusually moist air over the Andes, producing the lens-shaped clouds."
Winds and turbulence may have caused the elongated, trailing appearance that made the clouds resemble a school of fish, Mahmoud explained. These forces stretched and organized the clouds horizontally above the lake, while shadows cast onto the landscape accentuated their forms.
Santiago Gassó, an atmospheric scientist at NASA's Goddard Space Flight Center, agreed they were likely lenticular clouds, citing the environmental context and Patagonia's reputation as a hotspot for lenticular cloud formation.
"We can't identify them just from this one image," said Maria Hakuba, a research scientist at NASA's Jet Propulsion Laboratory. "The lens shape reminds me of lenticular clouds, which usually form near or over mountains." Lenticular clouds are created when prevailing winds are forced up and over a topographic barrier, often a mountain range.
Hazem Mahmoud, an atmospheric science lead at NASA's Langley Research Center, offered further insight into the phenomenon. MODIS data suggest cloud-top altitudes near 9,200 meters (30,000 feet) and cloud-top temperatures around 220 Kelvin, along with relatively large particle sizes consistent with the presence of ice crystals.
"It looks like we have a Cirrocumulus lenticularis," Mahmoud said. "Strong surface-level winds common in Patagonia likely swept across the glacial lakes of Los Glaciares National Park, forcing unusually moist air over the Andes, producing the lens-shaped clouds."
Winds and turbulence may have caused the elongated, trailing appearance that made the clouds resemble a school of fish, Mahmoud explained. These forces stretched and organized the clouds horizontally above the lake, while shadows cast onto the landscape accentuated their forms.
Santiago Gassó, an atmospheric scientist at NASA's Goddard Space Flight Center, agreed they were likely lenticular clouds, citing the environmental context and Patagonia's reputation as a hotspot for lenticular cloud formation.
It looks so cool! But also kinda weird. Scientists are saying it might be some kind of lenticular cloud, which forms when winds push air up against mountains. I guess the strong winds in Patagonia could have made them stretch out like a school of fish? 
️ It's crazy to think that something as random-looking as clouds can be caused by natural forces. And honestly, I'd love to see these clouds live! Can we get some footage of this on YouTube or something? 
I'm sure it's not like they have thousands of photos and data to review or anything. And hey, who needs concrete evidence when you've got a fancy-schmancy astronaut on the ISS with a sweet camera 
?
i mean, we're talkin 2025 here, and there's still like, wow moments in space 
. so, nasa scientists are all bent outta shape 'cause they can't figure out what these clouds are... lenticular clouds? maybe? cirrocumulus lenticularis? who cares? 
all i know is it looks like a bunch of fish swimmin together above the lake 
. just another day in space, folks!
! Can you even imagine being an astronaut looking out at that in space 
?! Anyway, from what the NASA scientists are saying, it sounds like they're pretty stoked to be studying this phenomenon. They're using all sorts of fancy equipment to try and figure out where these clouds came from and how they formed, but honestly, I think they're on the right track – lenticular clouds seem like a pretty solid explanation 
!
