I need some clarification about ash threat
It is almost ten years since I read this forum almost every day. I found an extaordinary amount of valuable and interesting informations. Some experts make here an extraordinary work. Bravo to all of them.
As I am only a SLF I refrained from posting until today (just reading up to now). I jumped over the fence because I have 2 facts that I am unable to fit with the general informations regarding the ash cloud and grounding of flights. This isprobably because I miss something and you may help me to know what.
1st fact:
All vulcanologists say that the present icelandic eruption is a small one (less than a cubic km of ash sofar) compared to some bigger eruption in the world which can throw up to several hundreds of cubic km of ash.
Iceland has several active volcanoes erupting each year with the same intensity or greater, sometimes several in the same time.
How can it happen that we were not hurt by the phenomenon during the last past 20 years? I found a partial answer in this thread : the jetstreams blow in an unfavarable and uncommon direction towards us. OK. But what is the usual direction ? The answer is also in this thread : directly from Iceland to the south mid-atlantic.
Therefore, what I do not understand is how transatlantic flights (some passing relatively close to Iceland) never cross ash clouds comming from active volcano in the past? It is hard to believe and apparently nobody has been frighten by this volcanic activity until nowadays. Why?
2nd fact
It happens that I was on board of a Lan Chile flight in april 2008 when the Chalten volcano has suddenly erupted with a HUGE eruption. Thru the window, I could see the huge column of ash although we were probably as far as 500 km away (a little south of Santiago). Fortunately for us, we were north-east of the volcano and the ash cloud was going straight to the west. BUT, the same week I had a phone call with my friends who live in Buenos Aires and they told me they could hardly breathe because of the volcanic smoke which was comming up to them right in the street of Buenos Aires (1500 km away from the volcano). As far as I know (I was watching at the announced schedules to see if my next flights were affected) none or very little flights have been canceled during this period. Including the flights BA - Calafate and BA - Ushuaia which were passing relatively close to the volcano downwind.
I ear that the present situation is very dangerous, enough to ground the entire european fleet, but this seems to me relatively uncompatible which what I described above. Please can somebody help me to find what it special with thr current volcanic activity?
By the way, it is not just free speculation, I expect to fly to Indonesia in 10 days from now if the gods and ATC permit.