The last time was a ridiculous fiasco with computer generated prediction flows which were totally inaccurate and for what?
You would think that Volcanic eruptions was something new like some unknown new virus that is plaguing the earth.
volcanic eruptions and volcanic ash has happened in different parts of the world since aviation begun.
There has never been a fatality in the history of aviation although there have been close calls flying into thick dense ash easily visible to the eye in daylight while flying in clear air.
The same excellent safety record regarding volcanic ash cannot be attributed to bird strikes which have killed people.
Yet we do not see bird tracking predictions in the migration season with big chunks of airspace closed down