Volcanic Ash Advisory Centre (VAAC)
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VAACs are responsible for advising aviation of the location and movement of volcanic ash clouds.
There are 9 VAACs covering the world as part of the International Airways Volcano Watch (IAVW) established by International Civil Aviation Organisation (ICAO). Each of the nine centres under the IAVW responds to reports of volcanic ash within their region and provides forecasts to the aviation community of ash cloud extent and movement. Observations may come from ground stations and volcano observatories, aircraft in flight or orbiting satellites. The ash warnings issued are in the form of Volcanic Ash Advisories and SIGMETs describing the current and future extent of ash.
- ICAO Handbook for International Airways Volcano Watch. This handbook is no longer subject to ICAO revision except for 'Part 5 - Contacts' for which they have set up a specific "latest version" at: 
- ICAO NAT OPS Bulletin - Effective: 16 May 2010 at 0001 UTC, recommended interim enhanced procedures to be implemented by States in the event of a volcanic eruption
- VAAC Map of Areas of Responsibility 2017