Editor’s note: This story is the answer to our March 2020 puzzler.
Russia’s Lake Beloye holds just over 6 cubic kilometers of fresh water; drops in a bucket compared to the 24,000 cubic kilometers in Lake Baikal, the world’s largest freshwater lake by volume). Yet Beloye still manages to make a stately appearance in satellite imagery.
On March 17, 2020, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite acquired this natural-color image of Lake Beloye in Russia’s Vologda region. It stands out in part because its water is shallowly spread across more than 1,000 square kilometers (400 square miles)—larger than the average lake area in this part of northwest Russia.
It also stands out because of the stark contrast of lake ice—some of it is likely snow-covered—with the surrounding landscape. The lake usually freezes over in early November and breaks up in late April. Thawing already appeared to be underway when this image was acquired, with thin gray ice along the southern coast near the historic town of Belozersk. If you click on this time series of raw images, small areas of open water were visible by March 30, before fresh snow appeared to cover the ice again on April 1.
The shape of the lake is strikingly round. Many of the lakes in this region fill valleys and depressions left behind at the end of the last Ice Age when the enormous ice sheets retreated. That could be the case here or, as another source points out, the water could be filling a 100-million-year-old impact crater.
While this image makes the lake appear isolated in the landscape, it’s actually connected to a series of rivers and canals that form the Volga-Baltic Waterway. In the area visible in this image, the waterway includes the Kovzha River, Lake Beloye, the Belozersky Canal (constructed along the lake’s southern side as a bypass), and the Sheksna River. This waterway, in turn, is connected to an even larger system of inland waterways known as the Unified Deep Water System of European Russia.
NASA Earth Observatory image by Joshua Stevens, using MODIS data from NASA EOSDIS/LANCE and GIBS/Worldview. Story by Kathryn Hansen.