Tanana Valley

The Tanana Valley is a lowland region of central Alaska on the north side of the Alaska Range, where the Tanana River emerges from the mountains. Much of the valley is underlain by permafrost, and its surrounding plains turn boglike in summer and are dotted with pingos, ice-cored mounds pushed up by freezing groundwater. Winters bring temperature inversions and thick fog, along with a katabatic wind known locally as the Tanana Valley Jet, which blows from the southeast to the northwest. It is the most populated part of Alaska north of the Alaska Range, centered on Fairbanks, and is home to the Tanana Athabaskans; sites such as Broken Mammoth and Swan Point, dated to roughly 12,000 to 14,000 years ago, contain some of Alaska's earliest evidence of human occupation.