About 30 years ago, there was a largish eruption[sup]1[/sup] of ash in a location that was west (about the same distance as Eyjafjallajökull is from Europe) of a heavily populated area. The wind was going east at the time, so the heavily populated area should have had a similar ash cloud over it.
As far as I remember, there was no suspension of airline flights except at those airports where a substantial amount of ash had fallen. Those were all fairly near the volcano and not in the heavily populated area.
So what happened then? Were the airplanes of the time damaged, but no one associated that damage with the volcano? Or they did associate it, but just lived with it? Or there wasn’t much damage to aircraft, which may mean they are being over-cautious with the current ash cloud? Or did the ash cloud actually go around the heavily populated area? (I’m fairly sure I remember reports of detection of the ash from that area, but memory is potentially wrong here.)
As for the big eruption in 1980, according to Wikipedia several airports were closed and over a thousand flights were canceled.
The U.S. is pretty large. The ash from Mount St. Helens royally screwed up air traffic in the affected areas, but as this map shows, most of the U.S. was not affected by ash, and much of the areas that were affected were not large population centers.
That second map is just where ash was found on the ground. I was talking about the ash cloud. There would have been one over the Midwest (which is roughly the same distance from St Helens as central Europe is from Eyjafjallajökull) and probably even further east. Any idea how far east these flights were cancelled?
I have vague memories of Mt St Helens ash being detected in places further east: I think on the east coast and in Europe, possibly in Asia too. This was within a few days of the erruption.
In terms of distance from the volcano, they’d have had to close airports from Denver to Chicago to match what the Europeans have done. That would have resulted in far more than just 1000 flights cancelled, even if they only did it for a few days.
As I recall, SeaTac airport was not actually closed by the May 18 erruption. The ash was carried strongly eastward, so Seattle didn’t get any. However, a number of flights from the east to Seattle were no doubt cancelled since they would have had to fly through the ash cloud. Seattle did get some ash from one of the secondary erruptions that followed. There was one a week after the main blast, one two weeks after (which I think is the one that went north to Seattle) and one a couple months later in July.
One of my pilot friends actually did have a close encounter with Mt. St. Helens ash while flying a King Air on business. He never saw ash, but the engines had to be overhauled/rebuilt and all the windows in the airplane replaced. His employer was not amused, but happy he didn’t crash. So, yes, it dd affect airplanes.
The Mt. St. Helens eruptions, though probably had a different composition and wind patterns may not have directed the ash cloud towards major airports or flights at the time.
A quick look at Widipedia indicates that the part of the eruption that generated an ash plume was of considerably shorter duration than that of Volcano-With-Unpronounceable-Name, so disruption to air travel did not continue for as long a time… Additionally, the interior of North America is not nearly as densely populated as Europe, and thus far fewer people were affected by any such disruptions.
