58.27 N, 154.98 W,
summit elevation 2047 m
stratovolcano with central caldera
Katmai volcano contains a lake filled caldera 4.5 x 3 km in diameter. A large eruption of Novarupta volcano in 1912 was previously attributed to Katmai. Caldera formation at Katmai was caused by lava drainage during the eruption of Novarupta.
Strong winds around Katmai volcano in Alaska caused the remobilisation of volcanic ash into the atmosphere on 26th September 2010. The volcanic ash was visible on satellite images and reached a height of 10,000 ft.
Strong winds at the volcano on 21st September 2003, remobilised old ash deposits, and produced ashfall on Kodiak Island 100 km away. No eruptions occurred at the volcano. Re-suspended ash was potentially hazardous to aircraft, since it reached an altitude of 2.1 km and drifted up to 400 km. A volcanic ash advisory was issued to warn pilots of the hazard.