What’s Volcanic Ash Advisory (VAA) Messages?

[Ref BOM Australia Knowledge Centre, VAA message]

Volcanic Ash Advisory (VAA) messages is a kind of SIGMET about volcanic activities.

Volcanic Ash Advisory (VAA) messages are issued by 9 Volcanic Ash Advisory Centres (VAACs) over the world. They are located in Darwin (Australia), Anchorage (US), Buenos Aires (Argentina), London (UK), Montreal (Canada) Tokyo (Japan), Toulouse (France), Washington (US) and Wellington (NZ).

How Volcanic Ash Advisory (VAA) Messages Looks Like?

  1. VA ADVISORY                 <——-  showing that it’s VAA message
  2. DTG: 20200420/1752Z   <——-  Date/Time (of issue) Group  – Year, month, day and time of issue (Zulu Time)
  3. VAAC: TOKYO  <——-  VAAC Name
  4. VOLCANO: KLYUCHEVSKOY 300260  <——-  Volcano Name and Number
  5. PSN: N5603 E16039    <——- Volcano position is given by latitude and longitude in degrees and minutes
  6. AREA: RUSSIA  <——- where the ash is located.
  7. SUMMIT ELEV: 4754M  <——- height above sea level, in metres and/or feet.
  8. ADVISORY NR: 2020/149 <——- Given in the format YYYY/N (YYYY : current calender year ; N : Each volcano has its own numbering sequence)
  9. INFO SOURCE: HIMAWARI-8  <——- Describes the means (e.g. pilot reports, satellite imagery, vulcanological authority) by which the VAAC was notified of the volcanic ash.
  10. AVIATION COLOUR CODE: NIL <——- alert level (refer picture below)
  11. ERUPTION DETAILS: VA DISSIPATED ON SATELLITE IMAGERY <——- summary by the information source.
  12. OBS VA DTG: 20/1720Z  <——- Observation Date/Time Group – in the format DD/HHMM (Zulu Time).
  13. OBS VA CLD: VA NOT IDENTIFIABLE FM SATELLITE DATA WIND FL180 320/30KT  <——- Observed Ash Cloud – Gives horizontal and vertical extent of the observed or estimated ash cloud, if known, plus an indication of the movement of the cloud.
    FCST VA CLD +18 HR: NO VA EXP  <——-  Gives the horizontal and vertical extent of the ash cloud at +6, +12, and +18 hours from the time of the observed cloud.
  15. RMK: NIL <——- Remarks
  16. NXT ADVISORY: NO FURTHER ADVISORIES=  <——- Gives the approximate date/time of the next advisory issue. The normal frequency of issue is every six hours, but some advices may be issued every twenty four hours.

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