Most likely the event was from an asteroid impact.
Here part of an article written in Rolling Stone about Cormac.
"ONE DAY A FEW YEARS AGO, after checking his mail and pouring his coffee, McCarthy gingerly made his way down the hall at the Institute. He passed the equation-scrawled windowpane, down the steps where Dr. Zen was curled in the corner, past the long, red sofa where a grad student lay sprawled, and into the corner office of his friend Doug Erwin. Then he started asking about the apocalypse. In particular, he wanted to know about extinction-the Cretaceous-Tertiary meteorite that wiped out the dinosaurs 65 million years ago.
Erwin is the guy to ask. A Smithsonian paleobiologist with a boyish fop of brown hair, Erwin is an expert on the subject: He wrote a book titled Extinction. He and McCarthy share a wry and fatalistic view of our time here on Earth. "The planet is going to do just fine without us," Erwin says. "We're an encephalized ape that won't last long."
Erwin told McCarthy about the likely aftermath of the deadly meteorite: the magnitude of the desolation, the collapse of ecosystems, the fallout of debris and gases. Then, one day last year, Erwin sat down to read a galley of The Road, which depicts the harrowing, post-apocalyptic journey of a father and son. Erwin smiled - so this is what McCarthy was up to, he figured.
He let his friend off the hook for the novel's intentional inaccuracies. "Instead of having gray skies that look like Beijing, it would actually be blue skies, like this," Erwin tells me one afternoon, as he motions outside his window to the hills rolling down toward Santa Fe. "There would also be a lot more ferns. But because of what he was trying to achieve, he had to take some artistic license. That book was about his son."
Nine years ago, after marrying for the third time, McCarthy became a father again. Soon after, in 2001, he was visiting Tennessee when the attacks of 9/
11 unfolded. Being a septuagenarian dad in the modern age is sobering. "When you're young and single, you hang out in bars and don't think about what's going to happen," McCarthy says. "But in the next fifty years when you have kids, you start thinking of their life and the world they have to live in. And that's a sobering thought these days. I'm not one of those conspiracy guys, but the world is in a very unstable situation. If you were to take thoughtful people on, say, January ist, 1900, and tell them what the twentieth century was going to look like, they'd say, Are you ****ting me?' "
McCarthy began to wonder about the future facing his boy. "I think about John all the time and what the world's going to be like," he says. "It's going to be a very troubled place." One night, during a trip to Texas with John, McCarthy imagined such a place. While his son slept, McCarthy gazed out the window of his room and pictured flames on the hill. He later decided to write a novel about it; The Road is dedicated to his son. While McCarthy suggests that the ashcovered world in the novel is the result of a meteor hit, his money is on humans destroying each other before an environmental catastrophe sets in. "We're going to do ourselves in first," he says.
In part, he blames an increasingly violent society. "If kids are unstable, they may very well be cranked up by the violence they see, and might do things that they wouldn't have done or would have taken them longer to get around to," McCarthy says. "But the real culprit is violence against children. A lot of children don't grow up well. They're being starved and sexually molested. We know how to make serial killers. You just take a Type A kid who's fairly bright and just beat the crap out of him day after day. That's how it's done."
