Valley of Ten Thousand Smokes, Katmai, Alaska, circa 1922

Valley of Ten Thousand Smokes in Katmai National Park, circa 1922. Windy Creek is in the foreground. Following the June 6, 1912 eruption of Novarupta-Katmai, thousands of fumaroles filled the valley for many years. Buried snow fields, glacial streams, and precipitation were converted to steam by the heat trapped in the pyroclastic flow. Learn more in USGS Professional Paper 1791: The Novarupta-Katmai Eruption of 1912--Largest Eruption of the Twentieth Century: Centennial Perspectives.