[LasVegasMac]

ummmm...actually you are right.

Given the prevailing winds - generally from west to east - the destruction to the west would only be a 100 miles or so. My guess, nothing more.

To the east, different story. Ash, measured in feet, a long ways from it. Like Nebraska.

Use Mt St Helens as an example. Complete blowdown and total destruction in what - 30 - 40 - 50 miles in the direction of the blast? I'd have to go looking again, but seems that I remember measurements of pyroclastic flows on the order of 100 miles or more. Again, I'd have to back that up with some research fact, for now, just some hazy memories.

While Mt St Helens was indeed an impressive event, it would not make a decent pimple on the ass of the order of magnitude of the two biggest events from YellowStone.

You say 100 miles. I'll have my toes closer to 1,000 - in any direction. With lots of cold beer. And hot dogs.

LVM

[Arthalion]

Given the prevailing winds - generally from west to east - the destruction to the west would only be a 100 miles or so. My guess, nothing more.

That may hold true with conventional volcanoes, but Yellowstone is no conventional volcano. When supervolcanues blow their top, the ejecta travels upwards and outwards in a parabolic arc in ALL DIRECTIONS...some scientists believe that supervolcano eruptions may even be powerful enough to blow some material into low orbit. The heat, speed, and density of the ejecta allow it to, at least temporarily, overpower the prevailing winds and rain ash on a roughly circular area around the vent...a 60MPH upper air current simply can't deflect a wall of ash that may be initially moving at several hundred miles an hour.

Of course, if I were within a couple hundred miles of this thing, I'd more worried about the mountain sized boulders raining down on my head than the depth of the ash fall!