Braxton Southwick is convinced a weaponized smallpox terrorist attack, or something similarly horrible, is inevitable.

He'sread Revelations. He watches news about nuclear saber rattling,financial meltdowns, mega-storms rendering populations helpless fordays. He is 40, and his research has led him to believe a biologicalattack "will happen in my lifetime."

Terrorists, he says, "would like to get a nuclear weapon, but I'm sure they'd take a pint of smallpox."

SoSouthwick and his wife, Kara, also 40, and their six children, ages13-21, have stored 700 pounds of flour, 600 pounds of sugar, 800 poundsof wheat, water, gas, diesel fuel, chemical suits, coal, charcoal, 14guns and eight chickens. They're ready to haul it in trucks and trailersto a cabin redoubt 90 minutes from their home in the West Jordan suburbof Salt Lake City if calamity hits.

They are part of a burgeoning"prepper" movement that believes preparing for the end of civilizationis more rational than ridiculing those who do. Once viewed largely as apractice by survivalists on the fringe, prepping has achieved cohesionand community in the Internet age through best-selling writers,bloggers, risk assessors, conspiracy theorists and companies that caterto preppers' needs.

The number of preppers is unknown, but a polldone for National Geographic Channel in September indicated that 28% ofAmericans knew one. Preppers meet-up networks are proliferating onsocial networks. Doomsday Preppers is the network's most-watched series, and the Southwicks are featured in the series premiere Tuesday night.

Gettingready for the end is not new, of course, or strictly American. Recallhow people across the USA dug fallout shelters during the Cold War.Doomsday prophets have been around as long as civilization. The federalgovernment was the ultimate prepper during the Cold War.

One ofthat era's icons remains - a massive underground bunker designed toprotect all 535 members of Congress and their aides against nuclear war.Dug into the Allegheny Mountains at the Greenbrier resort in WhiteSulphur Springs, W.Va., it once had 75,000 gallons of water, a powersystem, medical and food services, 30-ton blast doors, art of the lastdays of Pompeii and a mural of Washington scenery that was capable ofchanging leaves on the trees, depending on the season.

After its cover was blown by a story in The Washington Post in 1992, the bunker was abandoned by the government as an emergency destination.

Almost10 years later, the chaos of 9/11 prompted further calls for doomsdaycontingencies to protect the nation's leaders and sustain thegovernment.

You can tour this slice of underground history today.After the Southwicks visited the bunker recently, they said they felteven more strongly about the need to prepare. Their family reflects anew preparedness instinct that has been growing since the 9/11 terroristattacks. After that shock, the government urged people to store food,buy duct tape and roll water barrels into their basements.

Some went further.

Shelterbuilders saw a flurry of business right after 9/11, again after thefinancial meltdown in 2008, and in 2010, when predictions of a Dec. 21end of the world - derived from interpretations of a Mayan calendar -hit popular culture.

Skeptics question movement

JohnHoopes, a University of Kansas anthropologist and archaeologist, hasspent much time debunking the Mayan end-of-the-world predictions,arguing they are "contemporary hype ... invented by our culture andpromoted by the mass media." He blames, in part, a junk-science hangoverfrom the psychedelic drug culture of the 1960s.

Although it isprudent to prepare for storms or power outages, Hoopes says, goingunderground based on predictions from a long-vanished culture is simplyirrational. As for the prepper movement, he urges perspective. Therehave always been storms and earthquakes and threats from the unknown, hesays - they just weren't tweeted in real time.

Kenneth Rose, a University of California-Chico professor and author of One Nation Underground: The Fallout Shelter in American Culture, says the prepper movement raises "neighbor vs. neighbor" scenarios and "troubling class issues."

"Will the well-to-do only be able to afford these types of activities?" he asks.

"Frankly,I think people should put their energy into making a more peacefulworld, rather than contemplating saving their own skins," Rose says,adding that there is "no threat now that compares with the threat ofnuclear annihilation" during the Cold War.

Preppers don't buy that. Jay Blevins, a former deputy sheriff and SWATofficer in Berryville, Va., says social unrest from a financialmeltdown could be devastating. He has formed a prepper network of familyand friends, people with varying skills such as knifemaking. They'dhelp one another in such a calamity. He says his Christian faith driveshim to help others prepare, and although he is not certain the end isnear, he thinks getting prepared is an act of personal responsibility.

"We watch and pray," he says of his family's view toward doomsday scenarios.

Somepreppers have considered ramping up efforts since President Obama'sre-election last week, convinced it means the economy will soon collapsein a cascade of debt. Some are convinced Iran or another enemy isdeveloping an electromagnetic pulse weapon that would wipe out thepower, communication and transportation grids, rendering useless anydevice with a microchip.

Like the Southwicks - he a mechanic andformer professional bike racer, she an employee of a financial company -some preppers live normal lives on the surface. Underneath, they areprepared to live in a world apart.

The Southwicks are part of aseven-family neighborhood group that vacations together and makesdoomsday plans together. The neighbors know they can camp out at thecabin, Braxton says.

Others featured on Doomsday Preppersare more out there - literally. Robert and Debbie Earl, retired Floridachicken farmers, worry about the seas rising. So they are building ahome constructed of old tires and sand-filled bottles near Alpine,Texas. Robert Earl describes himself as "Mad Max meets Rube Goldbergwith a little bit of Al Gore thrown in."

A vulnerable world

A veritable industry has sprung up around the prepper movement. James Rawles, author of the non-fiction book How to Survive the End of the World as We Know Itand a pair of best-selling novels on survival, says 130,000 peopleregularly read his, where he and numerous contributorsprovide tips on how to prepare. The former Army intelligence officer has40 advertisers selling everything from seeds to silver, and 30 moreadvertisers on a waiting list.

"It's a growing recognition we livein a very fragile, very interdependent society, with long chains ofsupply and an increasing dependence on the power grid," says Rawles, whowon't say where he lives. "That dependence increases every passingyear, and the vulnerability of the infrastructure to technologicaldestruction increases by the year."

He says Superstorm Sandy's devastating impact on the populous Northeast ought to make the need for prepping obvious.

"Ifanybody had any doubts, if anybody was teasing their neighbors beforeSandy" for storing food or preparing a "bugout bag" of essentials, hesays, "they are not doing that anymore."

The day after Obama wasre-elected, Rowles posted, "Several readers have written to ask me if Iplan to stock up on more ammunition and magazines, now that the gungrabbers have further cemented their hold on Washington, D.C. My answer:No. I already have lots of ammunition and magazines."

The business of prepping

ScottHunt, who co-founded a South Carolina company called PracticalPreppers, says phone calls from potential customers increased the dayafter Election Day. "I am not going to make that correlation," Huntsays, "but you can."

Twenty months ago, Hunt, an engineer, andDave Kobler, a military veteran, started Practical Preppers to advisepeople how to stockpile and defend their homes.

Business forHardened Structures, an engineering firm based in Virginia Beach, is uproughly 40% since 2005, co-owner Brian Camden says. Some of his clientsbuy gold and silver and other precious metals as a hedge against apossible collapse of the currency, and they want to be able to protectit and their families, he says. So his company designs ways to buildunderground bunkers, strengthen walls and improve security systems onhomes.

Camden says he thinks a grid-destroying electromagneticpulse from a solar flare is the most likely threat but "afterinterviewing clients for 20 years, the one thing I do know is no oneknows for sure what will happen."

"The rise of al-Qaeda, Islamicterrorism, political divisions here in the U.S., the rich gettingricher, the separation of the economic classes," he says, describingwhat drives customers to him. "At the end of the day, it is assetprotection. Most people identify their family as their most importantasset. This is a family insurance policy."

The Southwicks sure see it that way. Braxton says his Christian faith turned him into an evangelist, urging people to prepare.

Braxton wrote a book, A Letter to My Friends,that includes the basics he preaches: Have emergency food and water inyour home, have a "bugout bag" for every person that includes water,food, clothes, a thumb drive of your financial and other vitalinformation, and other essentials.

Kara Southwick portrays herselfas "more of a realist" and is not convinced that the threats are asdire as her husband portrays them. But, she says, "We prepare foreverything."