"Considering that a commercial aircraft will travel about 150 km (80 M) in 10 minutes and that volcanic ash can rise to flight levels commonly used by turbine-engine aeroplanes in half that time, timely response to reports of volcanic ash is essential."
6000 fpm? maybe from the centre of the volcanic eruption but who will be flying over that?
If not that from what level are they talking about and where......
all this scientific detail is amazing.
Pace