Early spring around Hudson Bay in northern Canada is largely indistinguishable from winter. Sea ice still clings to land, and the boggy lowlands remain frozen. In the dulled tones of the boreal landscape, however, snow helps accentuate the area’s subtle topography. In late March 2026, an astronaut aboard the International Space Station captured this photo of frozen channels feeding Hannah Bay—a southern offshoot of James Bay, which is itself an extension of Hudson Bay.
Some of the patterns visible in the photo relate to the region’s ice age history. During the Pleistocene Epoch, the Laurentide Ice Sheet covered most of present-day Canada. It centered on Hudson Bay, where its immense weight depressed the land. Since the Last Glacial Maximum about 20,000 years ago, the ice has retreated and the land has been bouncing back. Glacial isostatic adjustment, or isostatic rebound, is relatively rapid around southern Hudson Bay; the surface continues to rise about 10 millimeters (0.4 inches) per year, or 1 meter per century.
The process has left a fingerprint on the newly emerged land. In this photo, faint, closely spaced ridges parallel the shore of ice-covered James Bay at the terminus of the Harricana river. These beach ridges formed from tidal action reworking sands and silts along the shore, with newer ridges developing along the water as land rises and relative sea level drops.
The Harricana and adjacent waterways flow through boreal peat bogs, or muskeg, in the Hudson Bay Lowlands on their journey out to sea. As the world’s second largest peatland complex, the lowlands store significant amounts of soil carbon. Elsewhere around the bay, the landscape retains features carved by glaciers, such as drumlins and eskers.
With the approach of summer, the muted colors of …