<Tr> <Th> Designated </Th> <Td> 1976 </Td> </Tr> <P> Redoubt Volcano, or Mount Redoubt, is an active stratovolcano in the largely volcanic Aleutian Range of the U.S. state of Alaska . Located at the head of the Chigmit Mountains subrange in Lake Clark National Park and Preserve, the mountain is just west of Cook Inlet, in the Kenai Peninsula Borough about 180 km (110 mi) southwest of Anchorage . At 10,197 feet (3,108 m), in just over 5 miles (8 km) Mount Redoubt attains 9,150 feet (2,700 m) of prominence over its surrounding terrain . It is the highest summit in the Aleutian Range . </P> <P> Active for millennia, Mount Redoubt has erupted four times since it was first observed: in 1902, 1966, 1989 and 2009, with two questionable eruptions in 1881 and 1933 . The eruption in 1989 spewed volcanic ash to a height of 45,000 ft (14,000 m). It caught KLM Flight 867, a Boeing 747 aircraft, in its plume . After the plane descended 13,000 feet, the pilots restarted the engines and landed the plane safely at Anchorage . The ash blanketed an area of about 7,700 sq mi (20,000 km). The 1989 eruption is also notable for being the first ever volcanic eruption to be successfully predicted by the method of long - period seismic events developed by Swiss / American volcanologist Bernard Chouet . As of August 2015, the Alaska Volcano Observatory has rated Redoubt as Aviation Alert Level Green and Volcano Alert Level Normal . </P> <P> The official name of the mountain is Redoubt Volcano, a translation of the Russian name "Sopka Redutskaya", referring to, as does the word "redoubt", "a fortified place". A local name, "Ujakushatsch", also means "fortified place", but it is difficult to determine if one name is derived from the other . The Board on Geographic Names decided on the name "Redoubt Volcano" in 1891 . </P>

When was the last time mount redoubt erupted