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A Pair of Hearts

Side-by-side downward-looking images show lakes shaped like hearts. On the left, Lake Saint Clair, near Detroit, is covered in blue-to-white ice with large cracks running through it. On the right, Salinas Las Barrancas in Argentina has a light pink-to-white appearance, and it is surrounded by angular green and brown fields.

Frozen Lake Saint Clair in the North American Great Lakes system and the briny Salinas Las Barrancas in Argentina have little in common—save for their heart-like shapes. From the perspective of Earth’s orbit, the opposites combine to send a lacustrine Valentine’s Day message.

In early 2025, a blanket of ice covered Lake Saint Clair. The OLI-2 (Operational Land Imager-2) on Landsat 9 captured this image (above left and below) of its cold countenance on January 27. Situated on the border of the U.S. state of Michigan and Ontario, Canada, the lake is part of the waterway linking Lake Huron to the north and Lake Erie to the south. A shipping channel running southwest-to-northeast is visible in the image. The Saint Clair River feeds the lake from the north, fanning out into a large delta and wetland area.

A satellite image shows the heart-shaped Lake Saint Clair covered in blue-to-white ice with large cracks running through it. The surrounding urban and agricultural landscape is snow-covered. On the lake’s northeast side, the top of the heart, a river splays into a delta. The Detroit River flows past the city of Detroit on the opposite side.

During the previous two winters, ice cover on the Great Lakes hovered at unusually low levels. But the winter of 2024-2025 has brought icier conditions. NOAA’s Great Lakes Environmental Research Laboratory (GLERL) tracks ice cover on Lake Saint Clair, along with the five Great Lakes. GLERL reported significant ice coverage persisting on the lake from early January 2025 through at least mid-February, in contrast with only a couple of icy weeks during the past two winters. Ice fishers have returned with tales of productive days catching yellow perch, walleye, and northern pike through the thick ice.

While January brings a chill to the Great Lakes, the Argentinian lowlands bake in the austral summer sunlight. On the plains near the port city of Bahía Blanca, the candy heart-like Salinas Las Barrancas (also Laguna de Salinas Chicas) exhibits a pastel pink hue. An astronaut aboard the International Space Station captured this photo (top right and below) of the lake in January 2024.

A photograph taken from the International Space Station shows Salinas Las Barrancas, a brackish lake in Argentina that has a light pink-to-white appearance. It is surrounded by angular green and brown fields.

With a lakebed below sea level, Salinas Las Barrancas collects water when it rains and is mined for salt when dry. Salt has been harvested here for decades, with thousands of tons hauled out for use in a variety of industries. In this brackish environment, salt-tolerant plants grow around the lake’s edges. Colorful birds such as the Chilean flamingo and endangered yellow cardinal are among the wildlife inhabiting the salt flats.

NASA Earth Observatory images by Wanmei Liang, using Landsat data from the U.S. Geological Survey. Astronaut photograph ISS070-E-76257 was acquired on January 16, 2024, with a Nikon D5 digital camera using a focal length of 500 millimeters. It was provided by the ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit, Johnson Space Center. The image was taken by a member of the Expedition 70 crew. The image has been cropped and enhanced to improve contrast, and lens artifacts have been removed. The International Space Station Program supports the laboratory as part of the ISS National Lab to help astronauts take pictures of Earth that will be of the greatest value to scientists and the public, and to make those images freely available on the Internet. Additional images taken by astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth. Story by Lindsey Doermann.

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