McMurdo Dry Valleys

77°28′S 162°31′E / 77.467°S 162.517°E / -77.467; 162.517

The McMurdo Dry Valleys are a row of largely snow-free valleys in Antarctica, located within Victoria Land west of McMurdo Sound.^[1] The Dry Valleys experience extremely low humidity and surrounding mountains prevent the flow of ice from nearby glaciers. The rocks here are granites and gneisses, and glacial tills dot this bedrock landscape, with loose gravel covering the ground. It is one of the driest places on Earth and is sometimes claimed to have not seen rain in nearly two million years,^[2] though this is highly unlikely and several anecdotal accounts of rainfall within the Dry Valleys exist.^[3][4]

The region is one of the world's most extreme deserts, and includes many features including Lake Vida, a saline lake, and the Onyx River, a meltwater stream and Antarctica's longest river. Although no living organisms have been found in the permafrost here, endolithic photosynthetic bacteria have been found living in the relatively moist interior of rocks, and anaerobic bacteria, with a metabolism based on iron and sulfur, live under the Taylor Glacier.

The valleys are located within the McMurdo Valleys Antarctic Specially Managed Area (ASMA-2).^[5]