Why is the Brooks Range the driest of Alaska's major mountain ranges?

The Brooks Range is considered the driest of Alaska's major mountain ranges because it receives less than 20 inches (500 mm) of annual precipitation.1

While Alaska's mountains span various climatic zones, the Brooks Range is situated in a region where its northern slopes fall within the Arctic zone, and its southern slopes are part of the continental zone. The continental zone is generally more arid than other parts of the state, characterized by clearer skies and more extreme temperatures. In contrast, other Alaskan mountain ranges, particularly those in the maritime zone along the southern coast, are heavily influenced by the Kuroshio (Japan Current), which brings significant cloudiness and high levels of precipitation.1