(Reuters) - When Patty Tegeler looks out the window of her home overlooking the Appalachian Mountains in southwestern Virginia, she sees trouble on the horizon.
"In an instant, anything can happen," she told Reuters. "And I firmly believe that you have to be prepared."
Tegeler is among a growing subculture of Americans who refer to themselves informally as "preppers." Some are driven by a fear of imminent societal collapse, others are worried about terrorism, and many have a vague concern that an escalating series of natural disasters is leading to some type of environmental cataclysm.
They are following in the footsteps of hippies in the 1960s who set up communes to separate themselves from what they saw as a materialistic society, and the survivalists in the 1990s who were hoping to escape the dictates of what they perceived as an increasingly secular and oppressive government.
Preppers, though are, worried about no government.
Tegeler, 57, has turned her home in rural Virginia into a "survival center," complete with a large generator, portable heaters, water tanks, and a two-year supply of freeze-dried food that her sister recently gave her as a birthday present. She says that in case of emergency, she could survive indefinitely in her home. And she thinks that emergency could come soon.
"I think this economy is about to fall apart," she said.
A wide range of vendors market products to preppers, mainly online. They sell everything from water tanks to guns to survival skills.
Conservative talk radio host Glenn Beck seems to preach preppers' message when he tells listeners: "It's never too late to prepare for the end of the world as we know it."
"Unfortunately, given the increasing complexity and fragility of our modern technological society, the chances of a societal collapse are increasing year after year," said author James Wesley Rawles, whose Survival Blog is considered the guiding light of the prepper movement.
A former Army intelligence officer, Rawles has written fiction and non-fiction books on end-of-civilization topics, including "How to Survive the End of the World as We Know It," which is also known as the preppers' Bible.
"We could see a cascade of higher interest rates, margin calls, stock market collapses, bank runs, currency revaluations, mass street protests, and riots," he told Reuters. "The worst-case end result would be a Third World War, mass inflation, currency collapses, and long term power grid failures."
A sense of "suffering and being afraid" is usually at the root of this kind of thinking, according to Cathy Gutierrez, an expert on end-times beliefs at Sweet Briar College in Virginia. Such feelings are not unnatural in a time of economic recession and concerns about a growing national debt, she said.
"With our current dependence on things from the electric grid to the Internet, things that people have absolutely no control over, there is a feeling that a collapse scenario can easily emerge, with a belief that the end is coming, and it is all out of the individual's control," she told Reuters.
She compared the major technological developments of the past decade to the Industrial Revolution of the 1830s and 1840s, which led to the growth of the Millerites, the 19th-Century equivalent of the preppers. Followers of charismatic preacher Joseph Miller, many sold everything and gathered in 1844 for what they believed would be the second coming of Jesus Christ.
Many of today's preppers receive inspiration from the Internet, devouring information posted on websites like that run by attorney Michael T. Snider, who writes The Economic Collapse blog out of his home in northern Idaho.
"Modern preppers are much different from the survivalists of the old days," he said. "You could be living next door to a prepper and never even know it. Many suburbanites are turning spare rooms into food pantries and are going for survival training on the weekends."
Like other preppers, Snider is worried about the end of a functioning U.S. economy. He points out that tens of millions of Americans are on food stamps and that many U.S. children are living in poverty.
"Most people have a gut feeling that something has gone terribly wrong, but that doesn't mean that they understand what is happening," he said. "A lot of Americans sense that a massive economic storm is coming and they want to be prepared for it."
So, assuming there is no collapse of society -- which the preppers call "uncivilization" -- what is the future of the preppers?
Gutierrez said that unlike the Millerites -- or followers of radio preacher Harold Camping, who predicted the world would end last year -- preppers are not setting a date for the coming destruction. The Mayan Calendar predicts doom this December.
"The minute you set a date, you are courting disconfirmation," she said.
Tegeler, who recalls being hit by tornadoes and floods in her southwestern Virginia home, said that none of her "survival center" products will go to waste.
"I think it's silly not to be prepared," she said. "After all, anything can happen."