An ash column reached 7 kilometres above sea level on Wednesday morning.
An 8 km high plume was recorded from the southernmost major stratovolcano on the Kamchatka peninsula.
The 7,000 year old volcano is the highest mountain in Russia outside the Caucases.
Klyuchevskaya Sopka's crater fills with lava amid new volcanic activity.
Hot ash tumbled down the mountain's southeastern slope as Bezymianny showed its power.
Group of tourists got stuck at 2,300m after helicopter blades froze.
A new air link between Alaska and the Russian Far East is opening up a new world of adventure tourism to US visitors.