If you felt like going for a walk in Los Angeles last Saturday afternoon you would have been well advised not to. The air quality was (as we say) “unacceptable.” There are so many things about life that are unacceptable but air quality is one of the few that gets an official designation. Above is how it looked from where I was. It looked way more dramatic elsewhere.
The sky was that color because of the “Sand Fire” which sounds a little more “end of the world” than it actually was. It was plenty serious enough – 37,000 acres of forest fire in the Sand Valley, about 30 miles north of the city, up near Santa Clarita, 10,000 people evacuated, 18 homes destroyed (all these figures provisional, of course), but the name invokes something even more extreme: dunes bursting into flame, sand particles turning into molten glass, something like Herzog’s Lessons of Darkness.
The LA Times helpfully ran an article under the headline “Air quality around Sand fire is 'like being around second-hand smoke,' expert says.” Some might have thought it was rather like being around first-hand smoke, but then we’re not all experts.
The man they’d got to pontificate was Mark Morocco, a clinical professor of emergency medicine at UCLA. “The danger posed by the Sand fire depends on how close people are to the flames,” he said. And did he have advice for walkers? Well not specifically. “For everyone, it is best to ‘throttle down on your exercise’ and get to places with better air quality, Morocco said.”
There was a psychological element too. “'People feel anxious about it when the sky looks like a zombie apocalypse, when the sky is red and these smoke plumes are on the horizon,' Morocco said. ‘If you have anxiety, you’re going to feel worse, or if you have depression, you could actually get depressed.’" You don’t say, Mr. Morocco.
Fact is, I’ve been watching the skies more closely than usual as I continue to read Gavin Pretor-Pinney’s The Cloudspotters Guide. Of course those weekend air conditions above LA weren’t clouds, which I suppose meant they couldn’t be spotted and named and classified. But the most interesting section I came across in Pretor-Pinney’s book was about cloud seeding by the Americans during the Vietnam War, “Project Popeye” as it was known, designed specifically to mess up the Ho Chi Minh Trail. This came as news to me though I’m sure not to many.
As I understand it, the Ho Chi Minh Trail was the supply route for men and equipment that ran from North to South Vietnam via Laos and Cambodia. This was a monsoon region, and when the rains came down. the trail became impassable. The American military boffins reasoned that the longer the rains went on, the more disruption there’d be. This was revealed to the American public in an article by Seymour Hersh in the New York Times, July 3, 1973. For years apparently the American military had been spraying chemicals (silver iodine seems to have been the active ingredient) into the clouds above Laos, Vietnam and Cambodia in order to make rain.
Frankly, the Ho Chi Minh trail doesn’t look like it was a walk in the park even at the best of times, although you could evidently get an elephant or two along at least part of it on a good day.
Project Popeye seems to have worked pretty well in itself, not that the US won the war or anything. And then there was also "Project Commando Lava," created by some guys at Dow Chemical. Aircraft dropped paper sacks filled with a mixture of Trisodium Nitrilo-triacedic acid and Sodium Tripolyphosphate. When mixed with rainwater this substance destabilized the soil and created “artificial” mud. In some quarters It gave rise to the slogan "make mud, not war.”
And that is something that the folks around Sand Valley (and elsewhere) will in due course have to worry about. It’s much the same every year around these parts. There’s a fire, scorched earth, destabilized soil, then the rain comes and creates mud slides (real, not artificial) even without chemicals. Anybody might think California was a war zone.