One hundred years ago today, the greatest volcanic eruption of the 20th Century occurred at Mount Katmai, Alaska. Mount Katmai, one of a chain of volcanoes in the upper Alaska Peninsula, erupted through a vent 6 mi (10 km) from its summit, releasing 30 times the amount of magma that erupted from Mount St. Helens in 1980. Photographer and author: Bill Burton USGS
Superheated pyroclastic flows roared down a U-shaped, forested, glacial valley to the northwest, scouring it clean and filling it with as much as 650 ft (198 m) of ash and pumice that then partially welded into solid rock.
After the eruption, the first explorers here encountered hundreds of fumaroles that were powered by residual heat from the ash flow deposit, hence the name “Valley of Ten Thousand Smokes”. The numerous fumaroles are the centerpiece of Katmai National Park and Preserve. This view down the valley, from the northwest spur of Baked Mountain, shows that not much has changed in the last 100 years other than the extinguishing of the “smokes.” The thin, draped deposits in the foreground are referred to as airfall — deposits of ash and pumice from the giant eruption column following emplacement of the valley-filling ash flow. To the right are the Baked Mountain huts, welcome shelter from the severe weather and sandblasting winds that often sweep the valley. Photo taken on June 10, 2011.