California's raging wildfires reached the vast Camp Pendleton Marine Corps base last night where they posed a direct threat to a nuclear power station, piling continued pressure on firefighters and rescue workers as the disaster moved into a fourth day. Although the hurricane-force desert winds that wreaked havoc earlier in the week had died down across much of the region, wind and fire patterns were still dangerous.

Marines began evacuating in the early hours from Camp Pendleton, a major launching station for missions in Iraq which covers a vast wilderness area just off the main highway from Los Angeles to San Diego. That highway was abruptly closed, cutting off the main line of communication between the two cities.

President Bush declared the situation in California a "major disaster" , which allows people affected by the fires to begin to receive federal grants even if they are uninsured. After meeting with the Cabinet at the White House, he told reporters: "I believe the effort is well coordinated. I know we're getting the manpower and assets on the ground that have been requested by the state and local authorities."

One of the two fires, dubbed the Ammo fire, started at the bottom of a local hillock called San Onofre Peak and threatened both a cluster of telecommunications equipment on the top of the hill and the nearby San Onofre nuclear reactor.

The President said that he was working closely with Arnold Schwarzenegger, the state's Governor, who has ordered air tankers to douse the flames before they could threaten the reactor, one of two controversial nuclear power plants in the state, both of them along the Californian coast.

Elsewhere, the vast firefighting effort yielded uneven results. The temperatures that have plagued southern California since the weekend showed no signs of abating until today at the earliest but humidity levels the earliest but humidity levels showed a modest rise and the winds died down from anything up to 110mph earlier in the week to about 30mph yesterday.

Some of the biggest fires in the outer suburbs of San Diego and the northern perimeter of Los Angeles County were slowly being tamed. The risk that the biggest of the blazes, the Witch Fire, could howl down the San Dieguito river valley and out to the exclusive beachside communities of northern San Diego County appeared to have subsided, although firefighters were still engaged in a huge battle to save the posh, gated communities, golf courses and horse paddocks of Rancho Santa Fe, just a few miles inland.

But other fires – one in the San Bernardino mountains east of Los Angeles and another on the remote eastern edge of Orange County, south of LA – continue to rage out of control, threatening tens of thousands of homes. Owners of weekend homes in and around Lake Arrowhead, two hours' drive east of downtown LA, made frantic inquiries about their properties, at least 100 of which had gone up in flames, but were unable to return to the scene because the fires were still too hot and proving too volatile. The overall toll from the fire was put at more than 400,000 acres – roughly equivalent to 56 sq m – with just shy of 1,200 homes lost. Just six people have been reported killed, although only one of those was consumed by the fires.

The area burnt is roughly on a par with the last big regional conflagration four years ago, although the death toll is far lower – 23 perished in 2003 – and the number of homes lost has been cut in half. Governor Schwarzenegger was quick to attribute those relative successes to prompt intervention the co-ordination and determination of local, state and federal agencies. "I think that American cities and states have learnt from the mistakes that were made in the past," Governor Schwarzenegger told reporters in San Diego, one of many stops he has made in the afflicted region in the past two days.

More than 600,000 people – some estimates have put the figure as high as a million – have been forced to evacuate their homes until the fires subside, representing the largest evacuation in California history. Some have already begun returning home. About 15,000 have ended up in shelters, Hurricane Katrina-style, although the shelters are very different from the dens of human misery seen in New Orleans and Houston.

(By Andrew Gumbel, The Independent, 25/10/2007)