(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
 (2) Issued:20250802/0153Z
 (3) Volcano:Klyuchevskoy (CAVW #300260)
 (4) Current aviation colour code:ORANGE
 (5) Previous aviation colour code:orange
 (6) Source:KVERT
 (7) Notice Number:2025-37
 (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 eruption of the volcano continues. Satellite data by KVERT showed that the ash plume continues to extended up to 240 km southeast of the volcano.

A summit explosive eruption of the volcano continues. Ash explosions up to 10 km (32,800 ft) a.s.l. could occur at any time. Ongoing activity could affect international and low-flying aircraft.
(12) Volcanic cloud height:5000 m (16400 ft) AMSL Time and method of ash plume/cloud height determination: 20250802/0120Z – Himawari-9 14m15
(13) Other volcanic cloud information:Distance of ash plume/cloud of the volcano: 240 km (149 mi)
Direction of drift of ash plume/cloud of the volcano: ESE / azimuth 108 deg
Time and method of ash plume/cloud determination: 20250802/0120Z – Himawari-9 14m15
(14) Remarks:
(15) Contacts: Dmitry V. Melnikov, IVS FEB RAS
dvm@kscnet.ru

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 02, 2025. KVERT, Institute of Volcanology and Seismology FEB RAS. URL: http://kvert.febras.net/van/?n=2025-37.
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]