Rich,
....and Yellowstone goes off every 600,000 to 700,000 years in a super eruption. We are at the 680,000 mark, so you have a 1 in 20,000 chance of this.
makes the 1 in 2,739,726 for something far less dangerous (assuming here that the inertia of the helicopter was sufficient to penetrate the building structure and get to the core) look a little irrelevant n'est pas?
Oh, and Yellowstone could go off tomorrow. Hi to all you Californians!!