I remember when this first came out, I questioned the severity based on the location of England in relation to Iceland and the prevailing winds.
It just didn't seem like such a major catastrophe to me.
But then ... I wasn't there, so what do I know.
The problem is that here in England the prevailing winds haven't been, er, prevailing. For many months we've had an unusually prolonged succession of northerlies, on the Eastern side of large North Atlantic high pressure systems. These brought us an exceptionally cold winter, a cold dry spring...and the ash. The prevailing moist, mild Atlantic southwesterlies have been rare visitors recently: although this week we're at last beginning to get some warmer westerlies.