(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
 (2) Issued:20251125/2011Z
 (3) Volcano:Bezymianny (CAVW #300250)
 (4) Current aviation colour code:ORANGE
 (5) Previous aviation colour code:orange
 (6) Source:KVERT
 (7) Notice Number:2025-140
 (8) Volcano Location:N 55 deg 58 min E 160 deg 35 min
 (9) Area:Kamchatka, Russia
(10) Summit Elevation:2882 m (9452.96 ft)
(11) Volcanic Activity Summary:An effusive activity of the volcano remains high, this is accompanied by powerful gas-steam emissions and numerous hot avalanches. Satellite data by KVERT showed a large thermal anomaly over the volcano last days with a high value of temperature difference between the thermal anomaly and the background; ash plumes from hot avalances extended for 50 km to the northeast of the volcano. The volcano is preparing for a paroxismal explosive eruption. KVERT continues to monitor Bezymianny volcano.

An effusive activity of Bezymianny volcano remains high, this is accompanied by numerous hot avalanches. Ash explosions up to 10-15 km (32,800-49,200 ft) a.s.l. could occur at any time. Ongoing activity could affect international and low-flying aircrafts.
(12) Volcanic cloud height:5500 m (18040 ft) AMSL Time and method of ash plume/cloud height determination: 20251125/1940Z – Himawari-9 14m15
(13) Other volcanic cloud information:Distance of ash plume/cloud of the volcano: 50 km (31 mi)
Direction of drift of ash plume/cloud of the volcano: ENE / azimuth 74 deg
Time and method of ash plume/cloud determination: 20251125/1940Z – 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, November 25, 2025. KVERT, Institute of Volcanology and Seismology FEB RAS. URL: http://kvert.febras.net/van/?n=2025-140.
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]