EVEN the colour of the usually pristine blue of Santa Monica Bay has appeared an ugly yellowish-brown—as the sun, filtered through a vast plume of smoke spilling out of the Los Angeles basin, has cast a jaundiced hue across the ocean. Coming on the heels of the region's driest summer on record, the dozen or more wildfires raging on the hillsides of southern California this past week were all too predictable.

In fact, the weather forecasters had it right almost to the hour. As the high-pressure system normally at higher latitudes swung south and inland, the humidity dropped early Sunday morning to below 10% when hot, dry Santa Ana winds roared predictably out of the high desert to the north-east of Los Angeles and barrelled down the mountain sides towards the coast—blowing down power lines and anything else in their path as they gathered momentum while funnelling through the canyons at tornado speeds.

AFP

Set-alight seen from satellite

The hillsides, with their undergrowth of waxy chaparral and uncleared thickets of dead trees felled by the drought's plague of pine beetles, were powder kegs waiting to explode. Sparks from fallen electricity cables lit the fuse. The hot, dry winds worked as bellows to fan the flames.

All perfectly normal. Or so it used to be until housing developers started carving up the hillsides. Now the aim is to prevent wildfires at all cost. But the measures half-heartedly taken are often counter-productive. Few home-owners clear the brush around their homes. Fewer still vote for bond issues needed to buy more fire-fighting aircraft, such as Bombardier's miraculous “Superscooper” amphibian.

But worst of all is an attitude of mind that seeks to deny the very existence of fire—and is then mortified when it happens.

In reality, fire is an integral part of nature, the mechanism by which much of vegetation regenerates itself. The prickly chaparral is a typical example of a tinderbox in search of a flint. Inedible to all but hardiest of creatures such as goats, the only way it can propagate itself is through providing enough oily fuel to catch alight. The shrub's hardier seeds then get carried aloft by the smoke and dispersed by the wind.

It was ever thus. In 1542, when the Spanish explorer Juan Rodriguez Cabrillo first sailed up the coast of California to where Los Angeles is situated today, one of the key observations he recorded was the plumes of smoke from fires burning in the Santa Monica Mountains. The Native Americans had learned to torch the hillsides to replenish the vegetation and provide better hunting. Subsequent Spanish, and later Mexican, ranchers in the area continued the practice.

Cabrillo also noted, incidentally, that an inversion layer of hot air blowing out of the desert overlaying colder air blowing in from the ocean had trapped the pollution from the fires to below a few hundred feet. Four centuries later this inversion layer was fingered as the main cause of Los Angeles' infamous smog—and the reason why, today, the world has vastly cleaner cars.

But their basin's unique geography and inversion layer have done little to alter Angelinos' thinking about fire. Instead of encouraging controlled burns, the current practice of total fire suppression has only increased the fuel load of the area's forested hillsides and canyons. So locals turn instead to technology to counter a problem they've helped create.

From his home overlooking Santa Monica Bay from halfway up the hillside, and a mere hop and a skip from where a fire ripped through Malibu canyon earlier this week, your correspondent has been keeping a weary eye on his mid-century enclave. With his high-pressure electric hose at the ready, he's been poised all week to douse any glowing embers the instant flames start licking his way.

With stuccoed walls and double glazing throughout, he's felt no need to break out the aluminium foil and paste it to the inside of the windows. Reflecting the heat of a passing firestorm this way helps reduce the chances of an unprotected wooden structure bursting spontaneously into flames.

Apart from installing garden sprinklers on his roof, your correspondent has been exploring the possibility of spraying his home each year before the fire-season gets underway with one of the latest hydrogel flame-retardants. One of the most popular retardants used by fire-fighters is Phos-Chek, made by ICL Performance Products in the Los Angeles area.

The formulation includes various ammonium phosphates and sulphates plus gums and clays. In the heat of the flames, the hydrates break down endothermically (ie, absorb heat from their surroundings) and help slow the combustion. Meanwhile, the sulphates and other additives create an insulation barrier between the burning and unburned timbers. The assorted gums and clays plus secret ingredients help thicken the mixture and prevent it from dispersing after being sprayed or dropped.

Though available in three colours, Phos-Chek usually comes as a red powder or liquid that gradually fades to an earthy brown. The red colouring helps aerial fire-fighters see where previous loads have been dropped.

Another neat thing about Phos-Chek is that, once things have cooled down, the phosphates and sulphates then act as fertilisers. A Russian product called OC-5, from the Leningrad Forest Research Institute in St Petersburg, is just as eco-friendly and even cheaper.

None of this, of course, would be necessary if Californians adopted the same low-tech solution used by their neighbours south of the border. Mexican authorities have sensibly introduced herds of goats into their hilly suburbs to keep the chaparral under strict control—and have suffered far fewer wildfires as a consequence. Your correspondent has been lobbying his neighbours and local officials to do the same. Unfortunately, everyone seems more concerned about their roses than their roofs.