 On December 7, 2013 activity at Kizimen and nearby Kliuchevskoi significantly increased, continued during November 29 - December 7, 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 volcanoes.