<i>"People who think a nuclear device is comparable to the energy released by a volcano just haven't seen a restless volcano up close. They are a whole lot bigger than they seem to be in the films. Mount St Helens is a relatively small volcano, yet it still took me nearly 6 hours to walk out of the center crater."</i><p>I can well attest to that. A year or so after the major eruption of Mount St. Helens on May 18, 1980, I had business in both Portland and Seattle and on that occasion I drove from Portland to Seattle rather than fly, as I'd normally do. (I'd been to Tektronix to whinge about ongoing problems we'd been having with a PAL 625 TV sync pulse generator—an interesting story in itself but I'll leave that for another time).<p>I live an ocean away—thousands of miles from Portland but I had an ulterior motive for renting a vehicle in Portland and driving to Seattle, as this time I wanted to visit and drive over the 'renewed' Tacoma Narrows bridge which replaced the infamous <i>Galloping Gertie</i> that failed in 1940—of which I'd learned so much about years earlier in structures and physics. Having a vehicle made that possible. Visiting Mt St Helens wasn't on my agenda—and I'd already seen it post the 1980 eruption from a commercial SFO/SEA flight although I did expect to see it in the distance to the east from the I5.<p>It was somewhat latish afternoon, 3:30–4:00 pm, when I arrived at my nearest point on the I5 to Mt St Helens and unexpectedly nearby there was a small airfield. Signs on the highway indicated that a company was offering joy flights to Mt St Helens, so on-the-spur-of-the-moment I decided to take the flight. Unfortunately, I was the only one wanting a flight at that time and the pilot told me that it was uneconomic to take only one person (two being the minimum) so I'd have to wait until additional sightseers turned up—and if that didn't happen soon (within 15 or so minutes) then it'd be too late in the day to fly! Anyway, I struck a deal at somewhat less than the amount for two people and we were on our way.<p>I don't need to describe this remarkable scene except to say it was spectacular—much more so than the somewhat limited view from the commercial jet; and anyone who's interested will already be familiar with the wonderful photos in <i>National Geographic</i> and elsewhere. However, one point I must comment on is that for mile after mile in this desolate lunar-mud-like landscape the remaining trunks of the flattened pine trees were all facing radially away from the exit point of the explosion like the spokes of a bicycle wheel, it was one of the strangest sights I've ever seen. There was no doubt that this was an extremely huge explosion.<p>After doing the standard joy flight, the pilot suggested that seeing I'd paid much more than the normal fare would I like him to take me closer to the crater. Gleefully, I agreed and we not only got closer to the crater <i>but we actually flew around inside it</i> — right, the crater is truly huge when one's actually inside it! When the author says it took him nearly <i>'six hours to walk out of the center of the crater'</i> he not exaggerating one iota.<p>'Tis a damn shame photos aren't allowed on HN, otherwise I'd post some of my old slides taken from inside the crater (they're truly spectacular).