Precisely the point. That's not an eruption, especially not for a volcano of that size. It's a minor belching.
We know the prevailing direction of deposit after dispersion in the lower atmosphere - just look at the map of Vvardenfell.
Apparently, you have little understanding as to what masses of ash are ejected in such an eruption. I point once again at major historical eruptions leading to a "year without a summer" on the other side of the planet and cities being buried in ash even beyond state borders by even "minor" eruptions such as Mount St Helens.
Of course it may prove fertile ground. But the eruption of Red Mountain could have been the same. Instead, it was reduced to a gimmick that does just what the author wants it to do. Likewise, the cultural fallout might be that the Dunmer, having already been driven partially underground as we hear, start fully emulating the Drow by becoming a matriarchic society in underground cities hating all surface life. Does it make sense? Not really? But neither does the fart of a volcano being described as an eruption.
Now, as for social and cultural fallout, how would followers of Azura throughout Tamriel react to a day with no dawn? How would they react to endless weeks with blood-red sunset? How would the Nord react if for a full year, the temperature doesn't get better than in deepest winter? How would Argonians react to a massive extinction and/or migration of species in their swamps as temperatures don't get high enough anymore for them to thrive? How would all people react to massive crops failures? Now that would have been something to chew on - but quite a massive amount of things to think about, and obviously, they thought it was too much to handle on top of the consequences of the Oblivion crisis. So instead of erupting, Red Mountain farted.
You have gone to a lot of trouble when MK just posted that it's not really about rl physics ^^ MK's post seems to state that the physical side is fallout from the metaphysics rather than cause and effect - no idea how that affects my own theorising because a lot of his thinking goes into areas that are outside my current interests. While I get some of his stuff there always seem to be spaces that are not filled in and so his the bottom line always seems to be one step beyond. That leaves the results of exterpolation open to error and so makes lateral thinking less useful. That may be the intention ^^
RED Mountain creation
... your post does provoke the query - where was it written that there was a 'nuclear' winter following the eruption? So I have to agree that it was not comparable to the event that created the sea and the island as others here have stated. but there is something there that jars as a lore thing. I remember reading that the Heart was thrown into the sea ... so there had to be a sea there in the first place - that infers that the either the crater came before the sea or the Heart came to be in Red mountain by another route.
The Map?
Ty for the stuff about the map - there is still no sign of the book on the shelves on this side of the pond
Volcanic Fallout, Hist and Argonians
What I was responding to in my posts were the questions of how other parts of Morrowind and Argonia were affected - and what the Hist were reacting to. Whatever the fallout it appears that Argonia was not hit as hard as Morrowind. So I was thinking that likely the Hist would take serious umbrage to anything that affected the levels of sunlight in their part of the world - they are trees right? And I guess that they would not bee keen on having tainted ash fall on their preserves. Also the reaction suggests that they are not that concerned about the Argonians as they did not appear interfere in the border wars with Morrowind nor care about the slavers who were abducting massive numbers of Argonians. but again it may be that they just see that as a vector that causes large numbers of Argonians to be seeded in the territory of their enemies
You are not happy with the novel?
Admittedly I was upset about the novel not being written by the in-game devs at first ... and the feeling gained from commentary here was that it was lacking ... but taking into account the content of in-game novels I have to accept that contradiction is the name of this game. Based on that it may be that the writer's style jars in some way - and that makes me wonder if that is just because he did not play the game or because he was following stuff that he had been told to include rather than his own instincts.
but I wasn't there when all this was decided and done - at least not to my knowledge - and I do not expect to learn further answers to that unless the book is published here
Hope this makes sense to you Irmo - laters