Novarupta

During the eruption a large quantity of magma erupted from beneath the Mount Katmai area, resulting in the formation of a 1.2-mile (2 km) wide, funnel-shaped vent and the collapse of Mount Katmai's summit, creating a 2,000-foot (600 m) deep,[7] 1.9 by 2.5 mi (3 by 4 km) caldera.

[17]: 3 [18] Eyewitness accounts from people located downwind in the path of a thick ash cloud described the gradual lowering of visibility to next to nothing.

[19] Ash threatened to contaminate drinking water and destroyed food resources, but the Alaska Natives were aided in their survival by traditional knowledge passed down through generations from previous eruptions.

[19] Pyroclastic flows from the eruption formed the Valley of Ten Thousand Smokes, named by botanist Robert F. Griggs, who explored the volcano's aftermath for the National Geographic Society in 1916.

[21] Established as a National Park & Preserve in 1980, Katmai is located on the Alaska Peninsula, across from Kodiak Island, with headquarters in nearby King Salmon, about 290 mi (470 km) southwest of Anchorage.

Novarupta geologic cross section
Colorful ash in the Valley of Ten Thousand Smokes