On 7 December activity at Kliuchevskoi significantly increased, prompting KVERT to raise the Alert Level to Red. Ash plumes rose to altitudes of 5.5-6 km (18,000-19,700 ft) a.s.l. and drifted more than 212 km NE and over 1,000 km E. According to a news article, a warning to aircraft was issued for the area around the volcano. The next day KVERT lowered the Alert Level to Orange. Ash plumes rose to altitudes of 5-5.5 km (16,400-18,000 ft) a.s.l. 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), United Press International (UPI)