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Winter’s arrival is no reason to hunker down indoors and avoid the outdoors until the spring thaw. Hitting snow-covered trails can be loads of fun, and icefishing has challenges for even the best anglers. However, the frigid temperatures can be hazardous if you don’t understand how to handle them.

Our bodies are generally efficient little furnaces, providing ample heat to keep us alive and comfortable. What it comes down to is knowing how to prevent that precious heat from being stolen. If you lose too much of it, hypothermia can result. When your body temperature falls below 95 degrees, a range of negative effects can result—from uncontrollable shivering to an increase in clumsiness to feeling drowsy and confused. This is a dangerous situation, but one that can largely be avoided with just a little forethought and planning.

There are four thieves that work hard at stealing our body heat every time we head outdoors. As we move along through these, something to remember is that cold isn’t really a thing. Rather, it is the absence of heat, just like how darkness is merely the absence of light. We get cold because we’re losing heat.

1) Radiation

We give off heat constantly. If you’re a parent, you know just how much of a “hot pocket” a baby can be. Radiating body heat is a byproduct of our energy consumption. It is just part of what keeps us alive. While we can’t do much to control how much heat our bodies radiate, we can limit how much is just entirely lost to the outside world. In cold weather, it serves to trap at least some of that warmth. The more insulating the material is, the more heat it will retain for us. All other things being equal, it is the loft—or how fluffy the material is—that will determine how well it will keep us warm. The little air pockets in the fluff are warmed by our body heat and the material itself keeps the warmth in place. Down and wool are two of the best choices in this regard, though the latter will still keep you somewhat warm when wet whereas down loses its insulating properties when soaked.

2) Convection

A side effect of that radiated body heat is that it warms the air immediately around us. Think of it like a fragile and thin blanket that surrounds us. If we’re sitting in one place and there’s little or no air movement, all is well. As a practical matter, though, that rarely ever happens when we’re out in the field. When we move about, or when the air blows over us, it moves that warm air blanket away. As that happens, we lose body heat through warming the cool air now around us, a cycle that continues to repeat until the circumstances change. The colder the wind is, the quicker we’re going to cool down.

We combat this similar to how we battle radiation heat loss, by wearing clothing that will keep that heat near our bodies for as long as possible. Windbreakers or another type of windproof outerwear will go a long way toward preventing cold outside air from stealing your body heat. Heat is lost particularly fast from areas of exposed skin, so be sure to wear a warm hat and a neck gaiter.

3) Conduction

This thief works by direct contact. Heat is transferred from one object, such as you, to another object, like a fallen log you decide makes a perfect bench as you take a snack break. One of the most common forms of conduction heat loss is sleeping directly on the ground. You might wake up shivering even in relatively mild temperatures.

Bear in mind that water is an excellent conductor of heat. For example, if you need to pick up a hot pan and you use a dry bandana as an oven mitt, you’ll be fine. On the other hand, if that bandana is wet, you may get singed. Similarly, if that log is damp when you sit on it, you’ll lose body heat quicker than it if was dry.

Incidentally, this is why cotton is a poor material for outdoor clothing. We like to use it for towels because it soaks up moisture really well. The problem when it comes to clothing is that it also holds on to that moisture just as well. That’s great when you’re cleaning up a spill, but not so awesome when it is holding your sweat against your back. That moisture on your skin will steal your body heat quite quickly. A better option is to use materials that wick sweat away.

The best way to combat heat loss through conduction is to avoid direct contact with objects that will sap your heat. This typically means using some sort of insulation. When bedding down for the night, use a sleeping pad to keep your body off the ground. When you take a break while hiking, don’t sit directly on a rock or log, use some sort of insulating layer, such as a blanket or even a spare jacket. If nothing else, pick up a cheap foam kneeling mat like gardeners use and stash it in your pack. They work well to keep your knees or butt insulated from the ground. This is also why a pair of good gloves should be in your pack when you venture out in cold weather. Handling metal gear like knives or stainless-steel bottles with bare hands is asking for trouble, especially in subzero temperatures.

4) Evaporation

Anyone who has worked up a good sweat hiking a steep hill and then relished the shiver from a cool breeze at the top knows that evaporation is a cooling process. In hot summer weather, this is one way our bodies work to keep from getting overheated. In the winter, sweat can kill you if you’re not careful.

As we mentioned earlier, water conducts heat quite well. If our skin becomes damp, whether that’s because we’re sweating from exertion or we’ve been caught in a sudden storm, heat transfers away from us rapidly. As the water evaporates, it takes our heat with it, leaving us shivering and miserable, possibly hypothermic if the condition persists.

One of the best ways to avoid evaporative heat loss is to wear layers. This way, as you warm up during a hike, for example, you can open up your jacket or even take it off instead of getting drenched in sweat. Then, when you take a break or otherwise come to a stopping point, you can bundle up again as you cool down. As a general rule, when I’m starting out on a hike, I prefer to feel a little chilled as I know I’m going to warm up as we go along.

In addition, you should do everything you can to avoid getting soaked by external sources of water, such as rain, snow, creeks, and the like. This means wearing or at least carrying the appropriate outerwear for the expected weather conditions as well as terrain. If you’re heading into an area that you know is riddled with streams and such, your footwear should be up to the task. Always have an emergency poncho with you, too, just in case the weather turns unexpectedly.