While looking at pics of volcanic ash encounters just remember that they represent the major degree of what is available in photos. Lesser degrees are not easily confirmed as anything more than accumulated everyday encounters with dirt.
EASA was buikding on this in their notice of proposed rule making while attempting to lay the onus on the manufacturers to define some level of wear out vs variable dirt that is OK.
I do use the word dirt because there are plenty of other particles out there other than from volcanos that will produce the same damage in varriable degrees. Accumulation vs time is the key to avoidance.
It is not the attempt to scare pilots to avoid all encounters but rather to alert pilots to minimize the accumulation of damage by controling the time and internal temperatures regarding the engines.
Most of the recomendations in this regard key on overt symptoms that require immediate action. It is anticipated that avoiding these symptoms as much as posible by route changes will allow us to operate safely and effectively.