Alaskan Airlines has been dealing with operations in and around volcanic activity for years but I believe they operated on a basic see and avoid basis combined with visual tracking of the ash cloud. Day VFR mostly until and this was approved by the FAA and all the tracking information was made available to all the airlines operating in and out of Anchorage. Undoubtedly some ash was ingested but low level amounts. I wonder why no-one in Europe made a phonecall and just said,
" Hey, kinda different for us, but we've had this volcano go off and we have no procedures in place for these kind of operations. Can you help us out? "
In aviation, as a sweeping generalization, it's nearly always happened before!
Oh well, back to reality, about to leave the ash and fly into the sand!