In virtually every survival situation that does not involve a medical emergency, protection from the elements rises to the top of the priority list. The human body quickly and easily suffers from overexposure to the sun, wind, cold, humidity or lack thereof. While there are tales of heroic survival situations suggesting that the human body can endure a great deal of torment and depravation (all of which is true), it is far better to prevent the suffering than to endure it. Proper shelter, established early in the game, is one of the best ways to avoid unnecessary physical and psychological distress.
The first line of defense, when it comes to shelter, is your clothing. Any time you leave the controllable environment of a heated and air-conditioned house or vehicle, your clothing becomes your most important shelter. We use and make adjustments to this shelter almost without thinking, as we turn up our collar against the cold wind, pull on gloves, or zip the coat a little higher. These actions can be compared to adjusting the thermostat at home, to keep ourselves comfortable and safe.
Proper selection of outdoor clothing is important, because you never know when you will have to rely on what you are wearing to keep you alive — at least long enough to improve on the shelter situation by finding or building a structure. Fabrics that turn the wind, refuse to absorb water, wick moisture away from the body, and dry quickly are most highly prized. Before the days of synthetics, wool was the material of choice (and still is for many outdoor enthusiasts) because it provided all of these desirable features to a limited degree. But now there are high-tech fabrics that offer wind and moisture protection, retain body heat, and are more lightweight and comfortable than wool. Cotton is comfortable, but absorbs moisture like a sponge, so it is generally avoided by serious outdoors people who are concerned about such cold-weather threats as hypothermia. Wearing several layers of clothing is best, because it allows you to add or subtract insulation and protection to match the conditions at the moment. And in hot, sunny weather, it's best to cover up with lightweight and lightly colored clothing to help prevent sunburn and slow dehydration.
Erecting a shelter actually plays several roles in a survival situation. First, it protects against the elements. Second, it may serve as a visual signaling device that can aid in a search and rescue operation. And third, it provides a powerful psychological benefit by allowing the individual to enjoy the relative comfort of a secure camp.
The best shelters are those that are tight against the wind and offer protection against precipitation. These are enemies of the human body, so staying dry and protected against either the blistering heat of the sun or the chilling wind is most important. Of secondary concern is that the shelter is secure from invasion of insects and animals. A third desirable feature is that the shelter be highly visible so it can attract the attention of potential search and rescue teams. Sounds like a colorful expedition-quality tent, doesn't it? But a high-zoot piece of camping gear may not always be available, so the survivor needs to know how to improvise.
Protection against the elements may be offered by something as primitive as a rocky outcropping, an overhanging ledge, the protected space created by the upturned root system or massive trunk of a downed tree. These natural shelters can be improved by using available brush, rocks, limbs, slabs of bark or whatever can be found in the area to further enclose the area. By paying attention to the direction of the prevailing wind and utilizing what nature has provided, a cozy enclosure can be constructed.
Perhaps you're lucky enough to have a few things with you that can be employed in making an emergency shelter. Something as inexpensive and lightweight as a pocket poncho can perform extremely well at turning the wind and rain. Propped up in lean-to fashion against a log or boulder, this simple expanse of plastic can keep you dry and protected from the wind.
If you're near a vehicle, the best shelter may be inside. However, if you're dealing with extremely high temperatures, taking refuge inside may be exactly the wrong thing to do. In that case, it may be preferable to remove the hood and prop it up to form a make-shift lean-to shade shelter. Or, the carpeting, headliner or door panels could be stripped out and put to similar use. When it comes to survival, don't worry about a little cosmetic damage to the vehicle — you're trying to save your life.
It's important to be careful about where you set up the shelter. Make sure it is on ground that is not infested with ants or other insects, and where the natural drainage of rainwater won't flood the camp. Try to establish a shelter whose opening takes advantage of the prevailing climate. North-facing would be best in hot weather, to avoid the direct glare of the sun. During cold weather, the shelter should face southeast so it can catch the earliest warmth of morning sunshine.
Once the elements are no longer a threat, attention should be turned to making the shelter as visible as possible, to aid in the search and rescue effort. Do anything that will attract the eye of a searcher. Clearing foliage around the area may help. Make tracks that lead to the shelter. Set up "unnatural" objects such as piles of rocks, or arrows on the ground made of small rocks that point to the shelter, or a message drawn in the hard soil. If you have a space blanket or other bright fabric, use it as an attention-getting cover for the shelter, or simply spread it out on the ground so it can be seen from a distance.