As a resident of Jackson Hole, this makes me a little nervous. (Scroll down the window in “Activity Update”.)

They closed part of Norris Geyser Basin last month, because of increased activity and temperatures.

The Yellowstone Caldera blows once every 600,000 years or so. It’s been 630,000 since the last one. I don’t know what the standard deviation is, so we might be overdue, or it could be good for tens of thousands of years more, but when it does, it will be the largest natural disaster in human history, dwarfing events like Mt. St. Helens, Krakatoa, Pinatubo by orders of magnitude.

It may not kill that many people directly (perhaps just a few hundred thousand), because the region is sparsely populated, relative to the rest of the country, but it would probably wipe out Gardiner and Boseman, Montana, and perhaps some towns in eastern Idaho. It will be, literally, a sound heard round the world. The ash would probably wipe out crops in the US for at least a year or so, and it could even kick off a new glacial advance if it cuts off the sunlight for a few years.

It would certainly be a distraction from the War on Terror. Also a good reason to make a little more effort in establishing extraterrestrial homes. We may be able to deflect killer asteroids, but it will be a long time, if ever, before we have the technology to circumvent an event like that.

Anyway, have a nice day.
[Update at 8:52 PM PDT]

Glenn points out a similar (though more local) threat that’s probably even more imminent.