WSVN — Many of us have a hard time grocery shopping for a week, or keeping enough cash in our wallet for a quick lunch, but some people are stocking up, preparing to live off the grid for months, even years. Because they believe, ready or not, a breakdown of society could be close at hand. 7's Craig Stevens has more.

If 9/11 taught us one thing, the unthinkable can happen without warning. Terrorist attacks, terrifying diseases, even technical glitches that could shut down our power grids.

Mike Morrison, prepper: "It would be chaos."

Like the 2003 New York blackout.

President George W. Bush: "I view it as a wake-up call."

Most Americans believe an across-the-board, catastrophic breakdown of our society could never happen, but others believe it could — and eventually will — happen.

David Mansell, prepper: "If there is an economic collapse, there won't be food in the grocery stores, and you're going to have to survive on your own."

They call themselves "preppers," as in preparing for a worst-case scenario.

Chris Petrovich: "I've been doing this for 30-plus years. We weren't preppers back then, we were survivalists."

They have food supplies to last for weeks, even months. And they have weapons to defend themselves.

David Mansell: "You're going to have people wanting to take things from you, and you gotta be ready for that."

There's even an organization called the Sustainable Survivalist Network, with 6 districts from Florida's Panhandle to the Keys.

Chris Petrovich: "We started with 10 people, and now at 2000 as of yesterday."

Two thousand Floridians who believe they need to be ready to live on their own if society breaks down.

Chris Petrovich: "What do you do if, God forbid, solar flares could take out our power grid or all the electronics are gone? We go over like, 'Well, how are you going to get in touch with your family if there is no way to communicate?'"

They are even learning to take care of themselves in case there are no hospitals.

Dr. Joe Alton: "I think that's very important to know, some very specific things: how to sterilize water, how to stop bleeding. You should know how to deal with orthopedic injuries."

Dr. Joe Alton and his wife Amy, a nurse practitioner, teach people how to prepare for medical emergencies.

On YouTube, they're Dr. Bones and Nurse Amy. They teach everything from stitching up wounds to setting broken bones.

Medical skills aren't the only things these preppers are learning. Some are also getting lessons in handling guns.

David Mansell: "Every prepper that I know owns a firearm."

David Mansell and Mike Morrison sell guns and other survival equipment at their shop in Pompano Beach.

Mike Morrison: "The real prepper isn't so much getting their food supplies in order, but they're getting a plan in order."

They're also secretive. Most preppers we spoke with didn't want to show us their stash.

David Mansell: "They don't want people to know what they have."

David and Mike loaded some of their supplies in an office at work, just to show us what it looks like. They believe, in a real emergency, people who are not prepared will come after those who are.

David Mansell: "They're going to want to take care of their family. Well, guess what? They're going to come after yours, and you got to be able to defend that."

But preppers do want people to be ready.

Chris Petrovich: "Even the government says you should have cash on hand, a couple of weeks' worth of medical supplies, your medicine."

Because if disaster does strike, you will have to deal with it, ready or not.

Preppers say many people here in South Florida practice prepping without even realizing it, when they collect supplies, food and water every hurricane season.