When the temperatures drop into single digits and the ground is covered with a blanket of snow, most sane people retreat to the warmth of their homes. There are some hardy souls who not only brave the bitter cold of winter, they embrace it. Skiers, snowshoers, snowmobilers and ice fishermen come to mind. In recent years their ranks have been joined by another wacky group - geocachers.

Winter geocaching is very satisfying. The crowds are home watching football on TV, the insects have died off, the rattlesnakes and copperheads are down for their long winter naps, poison ivy, weeds and undergrowth are gone and with no leaves to deal with the satellite reception is clear and strong.

Winter geocaching also poses some unique challenges. Caches are harder to find under the snow, frozen fingers don't operate the GPS buttons very well and if you aren't dressed properly you could die. Every year dozens of people succumb to hypothermia because they were unprepared for the weather.

Before you head out into the cold to find a cache, you need to take steps to ensure that you won't wind up as a human popsicle and become a statistic. The first thing to remember is COTTON KILLS. The same characteristics that make cotton so comfortable in the summer make it downright dangerous in the winter. Cotton retains water and loses its insulating properties when wet. So when dressing for winter cache hunts leave your cotton socks, jeans and sweatshirt at home.

The best materials for winter activities are synthetic fleece, wool and polypropylene. Synthetic fleece and polypropylene are hydrophobic materials, which means they don't hold water and will keep your body relatively dry. They, along with wool, also have the benefit of retaining some of their insulating properties when wet.

The key to staying warm in the winter is to dress in layers. Wearing multiple layers is better than a single heavy overcoat. Layers trap insulating air between them to help keep you warm. Also, layers can be removed and added as needed to keep you from overheating or getting too cold.

The ideal first layer is a thin polypropylene, or polyester undergarment. Polypropylene is sold under a number of proprietary names. Coolmax and Wickers are two popular brands of "polypro". Capilene is a popular brand of polyester. These materials have come a long way and are no longer the scratchy, uncomfortable material of 10 years ago.

The second layer should be polar fleece. This soft, comfortable material is most frequently sold under the brand name Polartec and comes in a variety of thicknesses. I recommend starting off with a thin polar fleece shirt, topped with a thicker one and finished off with a polar fleece vest or jacket. For the lower extremnities, a pair of polar fleece pants are perfect, but you don't want them to be too thick, or you might overheat. Wool also is acceptable for this second layer, but make sure it's real wool and not cotton knitted so that it looks like wool.

So now you have your first two layers. They will keep you dry - and warm if there is no wind. Unfortunately, in the winter there is usually wind and it is often brutal, so you will need a windproof outer layer. Since the first two layers are wicking the moisture away from your body, this outer layer will also need to be breathable so the moisture can dissipate. For this layer a waterproof-breathable shell is what's needed. Gore-Tex is the most popular of these. Its expensive, but a good Gore-Tex shell is worth the investment. Many manufacturers sell their proprietary brands of waterproof-breathable materials with varying degrees of breath ability. They are often cheaper than Gore-Tex and some work as well, but Gore-Tex is generally the standard among winter outdoors enthusiasts.

With your synthetic under layer, fleece middle layer and windproof and breathable shell you should set to head out into the cold. All you need to add are a good pair of hiking boots (or pac-style boots in very cold weather), a fleece scarf or neck gaiter, mittens and a warm hat and you will be ready for anything Mother Nature can throw at you. So what are you waiting for? Get out from in front of that TV and find some caches this winter.