Formed by glacial damming of the Flathead River during the last ice age, Flathead Lake [30 miles (48 kilometers) long and 12 to 14 miles (19 to 23 kilometers) wide] and Flathead Valley are featured in this southwest-looking, low-oblique photograph. Barely discernible north of the lake is the small city of Kalispell. To the east of the lake lie two rugged, deeply glaciated, snow-covered mountain ranges separated by an elongated glaciated valley. Also, east of Flathead Lake are the Mission Range and to the north Swan Valley and the Swan Range. Visible are numerous agricultural field patterns south of the lake in Flathead Valley and portions of the Salish Mountains west of the lake.