Survivalism -- the stockpiling of food and otherwise preparing for a possible end of civilization -- is often associated with isolated, rural and conservative Americans.
But liberals are now joining the movement in growing numbers, especially wealthy residents of Silicon Valley, thanks to fears fueled by Donald Trump's election in November.
Although survivalists have been around for many decades, the movement gathered momentum after a recent string of natural and financial disasters, particularly Hurricanes Katrina and Sandy and the global financial crisis of 2008.
Ron Douglas, who organizes survivalist shows to help people prepare for doomsday, says he has gone from staging an event a year with 5,000 attendees in 2010 to six events a year and 10,000 people.
Besides tornadoes, hurricanes and earthquakes, "preppers" -- liberal and conservative alike -- "are scared of civil unrest, government collapse, invasion from Russia and China," he says.
But while Republican survivalists who were twitchy under the Obama administration, anxiety is now mounting among liberals.
Before Trump's election, survivalists who came to Douglas's shows were mainly Republican white men. Today the crowds he draws includes men sporting dreadlocks and flip flops along with the more usual military-style outfits.
"More and more people are signing up from locations that are very heavily Democrat and asking questions that are unusual," he said.
"They're (showing) up saying that this election is the beginning of the end of civilization as we know it," Douglas said. "They're asking 'how do we prepare for nuclear fallout?' They're trying to get bunker information."
Facebook pages such as "Liberal Vegan Preppers" are also flourishing.
The movement also is attracting the super-wealthy, especially tech moguls from Silicon Valley, some of whom fear that unemployment caused by automation will further stoke social conflict.
- Billionaires and hideaways -
Numerous television shows attest to a fascination with the survivalist movement, including the reality TV show "Naked and Afraid," in which scantily clad candidates must survive in the jungle, and "Doomsday Preppers," which features a jury deciding who is best prepared to meet the world's demise.
"Since 2008, there's a rise of the populist movement and the one percent are much more aware of this," says Marvin Liao, a former Yahoo executive who is now a partner at 500 Startups, a venture-capital firm.
"The gap between the rich and poor has grown and there's some anger against the affluent class."
"If you're a billionaire, you probably have a hideaway," he added. "I do know people who have places in Canada, an island in the Caribbean, somewhere in Latin America, and New Zealand is very popular among certain people."
Another rich prepper, Antonio Garcia-Martinez -- a former executive at Facebook, Twitter and Goldman Sachs -- has a well-equipped home on an island near Seattle, in Washington state.
Liao, who describes himself as a "light" prepper, says Trump's presidency has heightened his fears of Armageddon.
His friend Adam Taggart, also a former Yahoo executive, left Silicon Valley several years ago to live in the Sonoma wine region north of San Francisco.
- Doomsday scenarios -
Besides Trump's election, mounting debt, inflation and the overexploitation of natural resources are also pushing Western society toward a doomsday scenario, Taggart says.
Taggart -- president and co-founder of PeakProsperity.com, which provides advice on building resilience -- lives a "semi-autonomous" life with his own orchard, poultry, pigs and enough canned food and water to last several months.
"We grow a percentage of our own calories," he says. "I'm not vulnerable to food having to be shipped."
He has a stash of cash and gold bars, a generator, a supply of wood and a water filtration system.
He also owns a "couple of guns" in case he needs to hunt for his own food.
To be on the safe side, he underwent laser surgery on his eyes to avoid having to wear glasses.
He hardly feels alone.
"There's less wealth disparity where I live now," Taggart says, adding that he has a group of prepper friends who meet on a weekly basis.
"If things were going bad, we would all band together," he said. "It's just amazing how hard it is to survive alone."