The Valley of Ten Thousand Smokes is a valley within Katmai National Park and Preserve in Alaska which is filled with ash flow from the eruption of Novarupta on June 6—June 8, 1912. The ash-filled valley covers a 40 square mile area and is up to 700 feet deep. In places deep canyons have been cut by the River Lethe, allowing observers to see the ash flow strata.
