(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
 (2) Issued:20251004/0430Z
 (3) Volcano:Kronotsky (CAVW #300200)
 (4) Current aviation colour code:ORANGE
 (5) Previous aviation colour code:red
 (6) Source:KVERT
 (7) Notice Number:2025-106
 (8) Volcano Location:N 54 deg 45 min E 160 deg 31 min
 (9) Area:Kamchatka, Russia
(10) Summit Elevation:3528 m (11571.84 ft)
(11) Volcanic Activity Summary:The phreatic explosive eruption of Kronotsky Volcano has likely ended. A cloud 272 x 84 km in size, containing water and some amount of ash, continues to move eastward from the volcano (the edge of the cloud is 190 km from the volcano to the east). The cloud height dropped to 5 km a.s.l. KVERT continues to moritor Kronotsky volcano.

The phreatic explosive eruption of Kronotsky Volcano has likely ended. Ongoing activity could affect low-flying aircraft.
(12) Volcanic cloud height:5000 m (16400 ft) AMSL Time and method of ash plume/cloud height determination: 20251004/0330Z – Himawari-9 14m15
(13) Other volcanic cloud information:Distance of ash plume/cloud of the volcano: 190 km (118 mi)
Direction of drift of ash plume/cloud of the volcano: E / azimuth 98 deg
Time and method of ash plume/cloud determination: 20251004/0330Z – 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, October 04, 2025. KVERT, Institute of Volcanology and Seismology FEB RAS. URL: http://kvert.febras.net/van/?n=2025-106.
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]