Eruption at Klyuchevskoy volcano reported up to 7 000 m (23 000 feet) a.s.l., Russia

Volcanic ash from Klyuchevskoy in Russia was reported at an estimated altitude of 7 000 m (23 000 feet) above sea level at 19:00 UTC on October 12, 2025. The advisory was issued by the Tokyo VAAC at 20:59 UTC on October 12, 2025.

According to the advisory, an eruption was observed with ash reported up to flight level 230, corresponding to approximately 7 000 m (23 000 feet). No volcanic ash cloud was detected in satellite imagery at 20:40 UTC. The information source included Himawari-8 and KBGS. No Aviation Color Code was stated in this advisory. There were no forecasts for ash cloud movement in the bulletin. The advisory noted further updates would be issued if ash becomes visible in satellite imagery.

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

Klyuchevskoy is a large stratovolcano located in Russia’s Kamchatka Peninsula and is known as one of the world’s most active volcanoes. Primary hazards include ashfall, pyroclastic flows, and lava flows. The nearest settlement, Klyuchi, lies about 30 km (19 miles) to the northeast and is at risk in the event of significant eruptive activity. Air traffic in the region can also be disrupted by volcanic ash clouds.