(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
 (2) Issued: 20190623/0107Z
 (3) Volcano: Raikoke (CAVW #290250)
 (4) Current aviation colour code: ORANGE
 (5) Previous aviation colour code: red
 (6) Source: KVERT
 (7) Notice Number: 2019-103
 (8) Volcano Location: N 48 deg 17 min E 153 deg 15 min
 (9) Area: Central Kuriles, Russia
(10) Summit Elevation: 1807 ft (551 m)
(11) Volcanic Activity Summary: The strong explosive eruption of the volcano began about 1805 UTC on 21 June. According to satellite data, ash emission continues, but last strong explosive event  with ash column up to 10-11 km a.s.l. occurred at 0540 UTC on 22 June. The large ash cloud on the height 10-13 km a.s.l. continue to drift to the east and north-east from the volcano, and a front of ash cloud unfolds from the south-east to north-west by a cyclone located in the area of Komandorskiye Islands. The edge of ash cloud front is located about 2000 km to the east-northeast of the volcano.

The explosive eruption of the volcano gradually finishing. Ash explosions up to 32,800-49,200 ft (10-15 km) a.s.l. possibly is remain. Ongoing activity could affect international and low-flying aircraft.
(12) Volcanic cloud height: 32,800-42,600 ft (10000-13000 m) AMSL Time and method of ash plume/cloud height determination: 20190623/0040Z – Satellite data, Himawari-8
(13) Other volcanic cloud information: Distance of ash plume/cloud of the volcano: 1240 mi (2000 km)
Direction of drift of ash plume/cloud of the volcano: 87 degrees - ENE
(14) Remarks:
(15) Contacts: Olga A. Girina, IVS FEB RAS girina@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://www.kscnet.ru/ivs/kvert/index_eng.php.
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, June 23, 2019. KVERT, Institute of Volcanology and Seismology FEB RAS. URL: http://www.kscnet.ru/ivs/kvert/van/?n=2019-103.
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]