KVERT reported that seismic activity at Kliuchevskoi did not exceed background levels during 19-26 November. Strong fumarolic activity was observed daily and an ash plume rose to an altitude of 5 km (16,400 ft) a.s.l. on 24 November. Satellite imagery showed a thermal anomaly over the crater during 19-21 November and a gas-and-steam plume that drifted 111 km NE on 24 November. The Aviation Color Code level was raised to Orange.

Based on information from the Yelizovo Airport (UHPP), the Tokyo VAAC reported that on 25 November an ash plume rose to an altitude of 7.9 km (26,000 ft) a.s.l. and drifted E. Possible eruptions detected in satellite imagery on 27 and 29 November produced plumes that rose to altitudes of 5.8 km and 6.7 km (19,000 and 22,000 ft) a.s.l., respectively, and drifted NE.

Geological Summary. Klyuchevskoy (also spelled Kliuchevskoi) is Kamchatka's highest and most active volcano. Since its origin about 6000 years ago, the beautifully symmetrical, 4835-m-high basaltic stratovolcano has produced frequent moderate-volume explosive and effusive eruptions without major periods of inactivity. It rises above a saddle NE of sharp-peaked Kamen volcano and lies SE of the broad Ushkovsky massif. More than 100 flank eruptions have occurred during the past roughly 3000 years, with most lateral craters and cones occurring along radial fissures between the unconfined NE-to-SE flanks of the conical volcano between 500 m and 3600 m elevation. The morphology of the 700-m-wide summit crater has been frequently modified by historical eruptions, which have been recorded since the late-17th century. Historical eruptions have originated primarily from the summit crater, but have also included numerous major explosive and effusive eruptions from flank craters.

Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Tokyo Volcanic Ash Advisory Center (VAAC)