(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
 (2) Issued:20250813/0309Z
 (3) Volcano:Klyuchevskoy (CAVW #300260)
 (4) Current aviation colour code:ORANGE
 (5) Previous aviation colour code:orange
 (6) Source:KVERT
 (7) Notice Number:2025-69
 (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:A summit explosive-effusive eruption of the volcano continues. A move of lava flows and ash emission from summit crater of the volcano continues. Activity of the volcano has decreased significantly. Satellite data by KVERT showed explosions sent ash up to 5-5.5 km a.s.l., and ash plume is extending for 302 km to the southwest of the volcano. The ash cloud 205x85 km in size continue to move to the southwest of the volcano on the high about 7-7.5 km a.s.l.

An extrusive-effusive eruption of the volcano continues. The danger of ash explosions up to 10 km (32,800 ft) a.s.l. remains. Ongoing activity could affect international and low-flying aircraft.
(12) Volcanic cloud height:5000-5500 m (16400-18040 ft) AMSL Time and method of ash plume/cloud height determination: 20250813/0230Z – Himawari-9 14m15
(13) Other volcanic cloud information:Distance of ash plume/cloud of the volcano: 302 km (188 mi)
Direction of drift of ash plume/cloud of the volcano: SW / azimuth 219 deg
Time and method of ash plume/cloud determination: 20250813/0230Z – Himawari-9 14m15
(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, августа 13, 2025. KVERT, Institute of Volcanology and Seismology FEB RAS. URL: http://kvert.febras.net/van/?n=2025-69.
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]