The Pleistocene landscape of western Nevada (about 15,000 years ago) was one of narrow mountain ranges and numerous interconnected lakes that together formed the glacial Lake Lahontan. The drying and warming of the regional climate since the last Ice Age led to the disappearance of the glaciers that provided meltwater and, eventually, to the disappearance of Lake Lahontan itself. Today, few remnants of Lahontan remain; most of its arms have become dry, enclosed basins known as playas.
This astronaut photograph highlights Walker Lake, one of only two remnants of Lake Lahontan that contain water throughout the year. (Pyramid Lake in Nevada is the other.) Walker Lake is located in an enclosed basin, bounded by the Wassuk Range to the west and the Gillis Range to the east. The lake is fed by the Walker River, which flows in from the north. The current dimensions of the lake are approximately 21 kilometers (13 miles) north-to-south by 9 kilometers (6 miles) east-to-west. Shoreline deposits form concentric bands that are just visible in the image; these rings record the varying lake levels when the water was higher in the geologic past.
The nearest town to Walker Lake is Hawthorne, Nevada. To the southwest, the highest peak of the Wassuk Range—Mount Grant (3,496 meters above sea level)—dominates the skyline. Green agricultural fields, primarily alfalfa, to the west of the Wassuk Range provide a striking contrast to the surrounding Great Basin desert. These fields are irrigated using water from the nearby East Fork of the Walker River.