Alaska Volcano Observatory

From Neal and others (1994): "On April 29, pilots reported a robust steam plume, possibly containing ash, emanating from the volcano. Subsequent satellite image analysis did not confirm ash emission and, on May 10, AVO staff on an overflight of the eastern Aleutian arc saw no ash on the flanks of the partially cloud-shrouded volcano. On May 25, the NWS received two pilot reports of an ash cloud rising to an estimated 35,000 feet (10.7 km); several SIGMETS were issued. NWS and AVO analysis of enhanced AVHRR satellite imagery indicated one or possibly two small cloud patches drifting northeast from the volcano out over the Bering Sea. Based on pilot descriptions and analysis of the satellite image, the eruption was deemed a short-lived burst and not a sustained ash emission event. U.S. Fish and Wildlife (USFWS) personnel aboard the R/V Tiglax observed fresh ash on the north and east flank of the volcano and evidence of small debris flows on the southwest flank. AVO staff identified a possible ash plume from Mount Cleveland on AVHRR imagery on October 20, however, no eruption was confirmed."