Editor’s Note: Today’s story is the answer to the May Puzzler<\/a>. The lake began draining<\/a> roughly 12,000 years ago, but its legacy remains visible across the region. In April 2026, an astronaut aboard the International Space Station snapped this photograph of farmland along the southern shore of Lake Winnipeg, where Lake Agassiz once deposited a thick, nearly flat bed of nutrient-rich silt and clay. Former lakebed areas like this one now support some of Canada’s most productive agricultural landscapes.<\/p>\n A grid-based land survey has also left its mark. The Dominion Land Survey<\/a>, one of the world\u2019s largest and most systematic surveying efforts, divided much of western Canada into one-square-mile sections after the Canadian government purchased Rupert\u2019s Land<\/a> from the Hudson’s Bay Company in 1869. The grid continues to define the layout of farm fields, roads, shelterbelts<\/a>, and drainage channels.<\/p>\n When the photo was taken late in the afternoon on April 19, a layer of snow and ice covered the landscape. The brightest, whitest blocks appear to be snow-covered farmland or icy ponds, while the darker areas are forests, wetlands, or exposed ground with less uniform snow cover.<\/p>\n Wheat, barley, oats, and canola are among the crops often grown in the area. In the upper part of the image, cottages and lake houses are clustered around Gull Lake, a popular site for boating, fishing, and other water sports. Common fish species found in the lake include northern pike, walleye, and yellow perch.<\/p>\n Astronaut photograph ISS074-E-494130<\/a>\u00a0was acquired on April 19, 2026, with a Nikon Z9 digital camera using a focal length of 560 millimeters. It is provided by the ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit at NASA Johnson Space Center. The image was taken by a member of the Expedition 74 crew<\/a>. The image has been cropped and enhanced to improve contrast, and lens artifacts have been removed. The\u00a0International Space Station Program<\/a>\u00a0supports the laboratory as part of the\u00a0ISS National Lab<\/a>\u00a0to 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\u00a0Gateway to Astronaut Photography of Earth<\/a>.<\/em> Story by Adam Voiland.<\/em><\/p>\n
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About 15,000 years ago, southeastern Manitoba sat beneath tens of meters of frigid water. Lake Agassiz<\/a>\u2014which once encompassed present-day Lake Manitoba, Lake Winnipeg, and Lake of the Woods\u2014covered an area larger than all of the Great Lakes combined. It formed in front of the retreating Laurentide Ice Sheet<\/a>, which dammed rivers that otherwise might have drained into Hudson Bay, producing an expansive body of water 1,100 kilometers (700 miles) long by 300 kilometers wide that spanned parts of today\u2019s Manitoba, Ontario, Saskatchewan, North Dakota, and Minnesota.<\/p>\n![\"Farm](\"https:\/\/assets.science.nasa.gov\/dynamicimage\/assets\/science\/esd\/eo\/images\/iotd\/2026\/farming-in-ancient-lake-agassiz\/ISS074-E-494130_lrg.jpg?w=4128&h=2752&fit=clip&crop=faces%2Cfocalpoint\")
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