Natural disasters like Hurricane Katrina can turn a high-tech culture into a decidedly low-tech one--where food, water and shelter are what matter most.

But that doesn't stop technologists from inventing devices for the disaster kit of the future. They're trying to provide for the most basic needs with technology that can turn sewer water into Gatorade, equip people with long-lasting lighting or save hypothermia victims without the use of electricity.

So if you're tech-savvy, and your home disaster kit already includes a flashlight, cans of food, bottled water, a first aid kit and plastic ponchos, then you may want to consider some advanced technologies for survival. After all, the U.S. government and the American Red Cross recommend that people prepare three days' worth of supplies and survival gear in the event disaster strikes. Katrina certainly underscored the merits of that recommendation. The following are some high-tech aids to augment a standard issue from the Red Cross:

A high-tech water dowser
Several companies are working on technology that can get potable water in any disaster, whether it be a flood, earthquake or shipwreck. Given that floods are the most common disaster in the United States, these items can come in handy.

"Nano mesh" is a nanotechnology water filter that can remove bacteria and viruses so that they're at levels better than Environmental Protection Agency standards, according to its inventor, Seldon Laboratories, based in Windsor, Vt.

Founded in 2003, Seldon developed a new type of membrane based on carbon nanotubes--materials whose dimensions are 1 billionth of a meter. Without using electricity, heat or chemicals, the membrane will remove bacteria, viruses, lead, arsenic and other compounds that can affect taste or purity in water. Its "waterstick," barely bigger than a pencil and capable of filtering a liter of liquid in 90 seconds, lets people suck ditch water like they would using a straw in a glass of water.

Seldon CEO Alan Cummings said a prototype of the waterstick is being used by doctors in Africa and that it will be available commercially next year. Future devices from Seldon that tap into nanotechnology will include a seawater desalinization technology, which should be available in 2007, and an air filter to protect against airborne diseases like Avian flu.

Hydration Technologies, based in Albany, Ore., and supplier to the military, also uses a membrane filter, but works by fluid osmosis. It is hydrophylic (attracts water) and allows water to pass through, yet blocks very small contaminants. The flipside of the membrane is flavored so it can turn dirty puddle water into Gatorade.

High-tech warmth
If you've ever been in snowy mountains during winter, you may be familiar with the hand-size thermal packs you squeeze and stuff in a glove to ward off frostbite. Techtrade, based in New York, has developed a full-body version of that, in the form of a high-tech blanket. The U.S. Department of Defense includes this blanket in its own survival kits to treat people with shock, burns or hypothermia.

Ted Bart, president of Techtrade, invented the formula for a specialized medical nonwoven fabric, which once opened, will heat up to 104 degrees Farenheit in 15 to 30 minutes and stay that temperature for eight hours. TechTrade uses so-called radio frequency technology to weld the nonwoven fabric of the blanket within six seconds in order to avoid a quick chemical reaction from the bio-component material contained within the fabric.

The disposable blanket, called Ready-Heat, was approved by the Food and Drug Administration last September and went public in October 2004. Boundtree Medical in Ohio and Gall's Emergency Medical Service sell the blankets commercially for between $30 and $50.

The power-free energy source
One of the most significant tech innovations for survival kits in recent years is improved battery life. Most brands of batteries used to have a shelf life of a year or two, but now they're marked with expiration dates of five to seven years.

"Literally, a few years ago you'd have to change your batteries every year to ensure they'd work in a disaster," said David Scott, president of LifeSecure, a maker of survival kits. And while Scott recommends a trustworthy flashlight or battery radio for all disasters, solar- or crank-powered radios are making the grade for the advanced kit.

The Sherpa X-Ray Wind-up Torch, from Freeplay Energy in the United Kingdom, lets people hand crank a dependable light source. A 30-second wind will create light for five to eight minutes, and a constant crank of 40 minutes will fully charge the Sherpa. The device uses a dual-filament bulb that lasts up to 20 hours. It sells for about $30.

Freeplay's Ranger radio gives people the option to power an AM/FM receiver with solar, crank or battery power. In direct sunlight, its external solar panel will simultaneously charge batteries and play the radio. It sells for about $40.

For extraordinarily long-lasting light, Articulated Technologies has developed a thin, flexible sheet of light made from semiconductors that will last up to 11 years once turned on. John Daniels, founder of the Higganum, Conn., company, said the LED (light-emitting diode) chips are placed between sheets of plastic, which are lightweight and can be wrapped around or hung on anything. The product will be sold commercially early next year, Daniels said.

Airborne dangers
Because many people die from smoke inhalation during a fire, the most common personal disaster, it's good to include an emergency portable oxygen cylinder with enough air to last more than an hour. E/Pax sells one for about $300.

Whether you want to be prepared for a breakout of the Avian flu or just want a Halloween costume, the breathable viral barrier suit from TechTrade will fit the bill. The full-body jumpsuit, made of three layers of nonwoven materials, protects against airborne viruses and contaminations like SARS, Asian blood flu and Anthrax.