Meteorological watch office

The Annex recommends that the occurrence of pre-emption volcanic activity, volcanic emptions and volcanic ash cloud should be reported without delay to the associated air traffic services unit, aeronautical information services unit and meteorological watch office.It also calls for special observations by aircraft whenever volcanic ash inter alia is encotmtered or observed and requires that each meteorological authority, on request and to the extent practicable, shall make available to any other meteorological authority, to operators and to others... 

Annex 3, id. at Standard 3.5. During the past few years a number of incidents have occurred due to aircraft encounters with volcanic ash clouds following volcanic eruptions. In order to provide for the observation and reporting of volcanic ash clouds and the issuance of warnings to pilots and airlines, ICAO, with the assistance of other international organizations, has established an international airways volcano watch (lAVW). The cornerstones of the lAVW are nine volcanic ash advisory centres which issue advisory information on volcanic ash globally, both to aviation users and meteorological offices concerned. 

---