I was stationed at Fairchild Air Force Base, just west of Spokane, when Mount St. Helens erupted in 1980. It was a beautiful, sunny (slightly overcast with fluffy white clouds) and calm Sunday morning. The base had opened its gates to the public for its annual open house. Because the roads on base were filled with cars, I hopped on my bicyle to take a liesurely wheeled wander. I was travelling west along the road that runs parallel and nearest to the flight line when I glanced at the horizon saw something that sent a bolt of primal lightning fear down my spine. There on that most beautiful and clear of late Spring mornings I saw a hideous, impenetrable blackness, a curtain of ink being pulled horizontally from west to east. Not yet aware that the mountain had blown, my first thought was, "This has got to be the most powerful thunderstorm in history!" At that moment a car drove past, radio loud, window open, and I heard a voice say something about the eruption--and I knew.
As the ink curtain of doom marched steadily toward the base, preceeded by a vanguard of billowing gray and white ash, I watched as pilots tried frantically to get their aircraft airborne. I remember we had an SR-71 in for the airshow that couldn't be prepared for an escape flight quickly enough; maintenance crews pulled some KC-135 tankers out of a large hanger and sheltered the SR-71 in their place.
By one o-clock that afternoon, it was darker than midnight. I watched the ash drop like dirty rain against the smothered light of the lightpole on the street corner in front of my house.
The full experience would take much more space than I care to take up now to relate.
I was almost what--200 miles--from ground zero? And Mount St. Helens was a relatively small eruption as eruptions go. That's about how far I am from Yellowstone now. Even a small burp from the Yellowstone super-caldera would be more than I would care to witness or be subjected to.
Keep those planes ready to go. God willing, that thing won't burp for millinea.