Ash cloud from Klyuchevskoy volcano reaches 10 km (33 000 feet) a.s.l., Russia

Klyuchevskoy volcano in Russia produced an ash cloud on August 6, 2025. The Tokyo VAAC reported volcanic ash at flight level 330 (approximately 10 km or 33 000 feet above sea level) extending east-southeast from the summit. The observation was made at 22:00 UTC and confirmed using satellite data.

According to the advisory, the ash cloud was observed at an altitude between the surface and FL330 (about 10 km or 33 000 feet a.s.l.), moving east at 15 knots. The ash plume is projected to reach up to FL350 (about 10.7 km or 35 000 feet a.s.l.) within the next 18 hours. No Aviation Color Code was specified in this message. The next advisory is scheduled for August 7, 2025.

The Smithsonian / USGS Weekly Volcanic Activity Report notes that eruptive activity at Klyuchevskoy’s summit crater continued during July 30 to August 5, 2025. Thermal anomalies were consistently seen on satellite imagery. A lava flow has been moving down the west-southwest flank since July 30, accompanied by phreatic explosions. Ash plumes have reached altitudes up to 7.5 km (24 600 feet) and drifted considerable distances.

Klyuchevskoy is a large stratovolcano forming part of the Kamchatka Peninsula’s volcanic arc. It is known for frequent explosive eruptions producing ashfall, lava flows, and pyroclastic flows. The town of Klyuchi, located about 30 km (19 miles) northeast, is the nearest population center potentially affected by volcanic activity.