Volcanic ash from Klyuchevskoy volcano observed at 8 230 m (27 000 feet) a.s.l., Russia

Volcanic ash from Klyuchevskoy volcano in Russia was observed at an altitude of 8 230 m (27 000 feet) above sea level at 23:20 UTC on October 14, 2025. The advisory was issued by the Tokyo VAAC at 00:00 UTC on October 15, 2025.

According to the advisory, ash emissions were continuing with the observed ash cloud reaching an altitude up to flight level 270 (approximately 8 230 m or 27 000 feet). The ash movement was towards the northwest at 19 km/h (12 mph). Portions of the ash cloud were obscured by meteorological clouds. The advisory notes that VAAC Anchorage also issued an advisory for volcanic ash at a lower altitude (FL230), but over or near the Tokyo VAAC’s area. No Aviation Color Code was stated in this advisory.

The most recent Smithsonian / USGS Weekly Volcanic Activity Report states that wind was no longer resuspending ash previously deposited on the north flank of Klyuchevskoy as of late September 2025, and only fumarolic emissions were observed. The Aviation Color Code was lowered to Green on September 25, 2025.

Klyuchevskoy is a large, active stratovolcano located on the Kamchatka Peninsula in eastern Russia. Known hazards include frequent ash explosions, pyroclastic flows, and lava flows. The surrounding region is sparsely populated, with the nearest settlement, Klyuchi, located approximately 30 km (19 miles) to the northeast. Volcanic ash from Klyuchevskoy poses a risk to air traffic across the North Pacific routes and can impact local settlements depending on wind direction.