In a survival situation, the single most important thing you can do1, is to build yourself a shelter. Think about it, when you're going on holiday, the first thing you want to do is to find your room and put your things in it. On a camping holiday, the first thing you do is to pitch your tent, or set up your caravan. In a survival situation, exposure is the biggest threat.
In hot weather, you need shelter from the sun and rain, and in cold weather (or at night, when it's often quite cold), you need warmth and shelter from rain.
Why a Debris Shelter? And What's that about a Squirrel?
Although natural shelters (windbreaks, brush piles, thick bushes, fallen trees, rock piles, caves) are fine for short periods, in a survival situation the debris hut comes into its own. Natural shelters may only protect against certain things, but may not be good in other conditions; for example, rain. They may be subject to collapse and also harbour dangerous snakes and insects.
A debris shelter is built on the same lines that a squirrel uses to build the nest - cosy and snug, well insulated and rain-resistant. More about this later.
Location, Location, Location
A good shelter built in a poor location is a poor shelter and a good location can improve a mediocre shelter. Look for a place:
Away from water - At least 50 yards/metres. Near to water, the land will be damp, which can lead to the body losing heat, even on warm nights.
In a well drained area - Look for drainage marks or run-off channels. If possible, choose somewhere slightly higher than the surrounding area so that water runs away from the shelter.
Away from thick forest or the centre of a field - Thick forests are damp places and shielded from the warmth of the sun, even on warm days. The centre of a field will have no natural wind breaks or buffers from wind or bad weather.
Away from poisonous plants or insect nests, eg, ants' or wasps' nests.
Away from other potential dangers, eg, dead trees, or places where there may be rock or mud slides.
Where there is enough debris and material to build the shelter - If you have to carry the building materials a long way, you may expend more time and energy than you can afford.
The Squirrel Principle
Squirrels build their nests with an internal skeleton that keeps the inner insulating material in place and houses the sleeping place. The outer shell of the shelter is held in place by a lattice work of sticks, which keeps the outer debris from being blown away. It helps keep the structure together even in violent weather.
To build a debris shelter, you will need a prop, which could take the form of a sturdy sapling, log or rock, which will need to be strong and no higher than crotch height from the ground. You will also need a sturdy ridge-pole, a little longer than your height with an outstretched arm, held high above your head. One end of the ridge-pole should rest on the ground and the other should be braced on the prop and secured with other props.
Before placing the ridge-pole in place, you should check where the prevailing wind is coming from, so that you can site the entrance away from it. Wind and rain blowing towards the entrance will take the heat from the shelter.
Once the ridge-pole is in place, you will need to place ribbing close together along both sides at an angle, leaving an opening for a door. At this stage, it will look like a backbone with ribs in an inverted 'V' shape. Before going any further with construction, crawl inside and make sure that the shelter is both snug and allows free movement.
You will next need to pile a generous assortment of fine brush over the entire shelter, creating a netting effect. This will support the outer debris and keep the inner debris in place.
It's now time to collect the debris to put in and on the shelter. You'll need to protect your hands doing this, so it's a good idea to use forked sticks to rake up piles of dead leaves, dried ferns, forest litter, grasses, mosses, to create dead air space. If the ground is covered in snow, you can use pine and evergreen branches, however you will need to use lots more to create enough dead air space, as green material tends to flatten unlike dried vegetation.
After you have piled up the debris on the shelter (it should look like a huge dome), you can weave sticks round the door. As a refinement, you could think of putting a log or branch at ground level to prevent wind from blowing in2. In summer or autumn, it will need about 2 ft/60 cm thick, in winter, 3-4 ft/1 metre thick.
Once you have sufficient debris in place, you will need to place a layer of light sticks on top to hold the debris in place, otherwise a strong wind could strip it all off. Note, you should not use heavy sticks as these would compress the debris and you would lose the insulating properties!
Once the outside is complete, you will need to stuff the inside with the softest, driest debris you can find. Stuff it from top to bottom, crawl inside to compress it, stuff it again. Even if it is wet, this shelter will keep you warm.
You should enter the shelter feet first, working your way to the upper part of the shelter. This will make sure that you have enough insulation from the ground. You shouldn't need to plug the door unless it's well below freezing. No need for a sleeping bag here!
Never light matches or fires anywhere near your debris hut. It is like a tinder box.
In a survival situation, make sure your hut is well marked, as it will be well camouflaged. This will allow searchers to find you more easily.