(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
 (2) Issued:20250820/2318Z
 (3) Volcano:Klyuchevskoy (CAVW #300260)
 (4) Current aviation colour code:GREEN
 (5) Previous aviation colour code:yellow
 (6) Source:KVERT
 (7) Notice Number:2025-81
 (8) Volcano Location:N 56 deg 3 min E 160 deg 38 min
 (9) Area:Kamchatka, Russia
(10) Summit Elevation:4750 m (15580 ft)
(11) Volcanic Activity Summary:The explosive-effusive eruption of the volcano occurred from 20 April to 16 August, 2025 with ash removal up to 11.5 km a.s.l. Currently, only fumarole activity of the volcano is observed. KVERT continues the monitor of the Klyuchevskoy volcano.

A gas-steam activity of the volcano continues. Ongoing activity could affect low-flying aircraft.
(12) Volcanic cloud height:NO ASH CLOUD PRODUSED
(13) Other volcanic cloud information:NO ASH CLOUD PRODUSED
(14) Remarks:
(15) Contacts:Dr. Olga A. Girina, Head of KVERT, IVS FEB RAS
girina@kscnet.ru +74152202044

Duty scientist: +79622825253
(16) Next Notice:A new VONA will be issued if conditions change significantly or the colour code is changed. VONAs are posted at http://kvert.febras.net.

In Russia, KVERT, on behalf of the Institute of Volcanology and Seismology (IVS) FEB RAS, is responsible for providing information on volcanic activity to international air navigation services for the airspace users.

CITATION GUIDELINES

For formal scientific citation of this VONA/KVERT Information Release, please use the following:
VONA/KVERT Information Release, August 20, 2025. KVERT, Institute of Volcanology and Seismology FEB RAS. URL: http://kvert.febras.net/van/?n=2025-81.
Aviation Colour Codes

GREEN

Volcano is in normal, non-eruptive state

   or, after a change from a higher level:

Volcanic activity considered to have ceased, and volcano reverted to its normal, non-eruptive state.

YELLOW

Volcano is experiencing signs of elevated unrest above known background levels.    

 or, after a change from higher level:

Volcanic activity has decreased significantly but continues to be closely monitored for possible renewed increase.

ORANGE

Volcano is exhibiting heightened unrest with increased likelihood of eruption.

   or,

Volcanic eruption is underway with no or minor ash emission.
[specify ash-plume height if possible]

RED

Eruption is forecast to be imminent with significant emission of ash into the atmosphere likely.

  or,

Eruption is underway with significant emission of ash into the atmosphere.
[specify ash-plume height if possible]