Monday, December 10, 2012

Wilderness Survival - Part 3, Shelter




Once one has calmed one’s nerves and relaxed (see part 2 of this series), the next imperative for wilderness survival is shelter.  The reality is that hypothermia kills quickly.  Hypothermia in simple terms is just a cold body.  I am not talking about cool skin or a mild case of the shivers.  Hypothermia means that heat is leaving your body faster than your body can replace it.  If this goes on for very long at all, weird things start to happen. 

According to Wikipedia, these are the stages of hypothermia.

Mild

Symptoms of mild hypothermia may be vague[13] with sympathetic nervous system excitation (shivering, hypertension, tachycardia, tachypnea, and vasoconstriction). These are all physiological responses to preserve heat.[14] Cold diuresis, mental confusion, as well as hepatic dysfunction may also be present.[15] Hyperglycemia may be present, as glucose consumption by cells and insulin secretion both decrease, and tissue sensitivity to insulin may be blunted.[16] Sympathetic activation also releases glucose from the liver. In many cases, however, especially in alcoholic patients, hypoglycemia appears to be a more common presentation.[16] Hypoglycemia is also found in many hypothermic patients because hypothermia often is a result of hypoglycemia.[17]


Moderate

Low body temperature results in shivering becoming more violent. Muscle mis-coordination becomes apparent.[18][19][20] Movements are slow and labored, accompanied by a stumbling pace and mild confusion, although the victim may appear alert. Surface blood vessels contract further as the body focuses its remaining resources on keeping the vital organs warm. The victim becomes pale. Lips, ears, fingers and toes may become blue.


Severe

As the temperature decreases further physiological systems falter and heart rate, respiratory rate, and blood pressure all decreases. This results in an expected HR in the 30s with a temperature of 28 °C (82 °F).[15]
Difficulty in speaking, sluggish thinking, and amnesia start to appear; inability to use hands and stumbling is also usually present. Cellular metabolic processes shut down. Below 30 °C (86 °F), the exposed skin becomes blue and puffy, muscle coordination becomes very poor, walking becomes almost impossible, and the person exhibits incoherent/irrational behavior including terminal burrowing or even a stupor. Pulse and respiration rates decrease significantly, but fast heart rates (ventricular tachycardia, atrial fibrillation) can occur. Major organs fail. Clinical death occurs. Because of decreased cellular activity in stage 3 hypothermia, the body will actually take longer to undergo brain death.[citation needed]


Paradoxical undressing

Twenty to fifty percent of hypothermia deaths are associated with paradoxical undressing. This typically occurs during moderate to severe hypothermia, as the person becomes disoriented, confused, and combative. They may begin discarding their clothing, which, in turn, increases the rate of heat loss.[21][22]
Rescuers who are trained in mountain survival techniques are taught to expect this; however, some may assume incorrectly that urban victims of hypothermia have been subjected to a sexual assault.[23]
One explanation for the effect is a cold-induced malfunction of the hypothalamus, the part of the brain that regulates body temperature. Another explanation is that the muscles contracting peripheral blood vessels become exhausted (known as a loss of vasomotor tone) and relax, leading to a sudden surge of blood (and heat) to the extremities, fooling the person into feeling overheated.[23]


Terminal burrowing

An apparent self-protective behaviour known as terminal burrowing, or hide-and-die syndrome,[24] occurs in the final stages of hypothermia. The afflicted will enter small, enclosed spaces, such as underneath beds or behind wardrobes. It is often associated with paradoxical undressing.[25]


I told you it was weird.  So, first you shiver, then you get disoriented, then you stumble, your lips turn blue, you start slurring your words, and then you can’t think straight.  You start to walk like a zombie, and then you start thinking that the solution is to take off all your clothes.  Huh?  Take off your clothes because you are freezing to death.  Ugh.  Next comes the terminal burrowing.  Wait! Rewind!  Terminal burrowing?!!  How about live-saving burrowing!  That needs to start way, way back in the “I might not get to the car in time so I think I will build a shelter” phase.  This will eliminate the rest of the symptoms.

I had a friend who died outside of her half built snow cave.  Terminal burrowing.  This is no joke.  What is shelter, really?  What does it look like in the wilderness?  If people would just burrow BEFORE they are freezing to death, then they would not freeze!



The simplest shelter does not seem like shelter at all.  The first shelter is simply insulation.  The animals have fur and feathers that they fluff up to stay warm.  Being the nearly hairless human kind, we can’t fluff up our hair.  Oh we try.  That is what goose bumps are for.  But with our limited hair follicles, goose bumps don’t quite cut the bill.  We need to use our gray matter rather than our fur.  If you don’t have enough layers on (you should have planned for that with a fleece and shell in the pack), then it is time to stuff it.  Stuff your clothes with lots and lots of light, DRY, fluffy stuff.  Tuck your shirt into your pants.  Tuck your pants into your socks.  Fill up your clothes with dry fine grass, or cattail fuzz, or dry leaves, or whatever is available.  This will create a very warm cocoon for you.  But don’t stop there.  If you doubt getting to the car in time, then build a shelter early.  Right away!  Don’t wait until it is too late. 

I suppose I should mention that of course, you have a nice warm sleeping bag in your pack, and the dry body heat of two people will keep them much warmer than one.  Get off the cold wet stuff, and get in that bag together.  Don't be shy.  Get rid of anything that is wet and save a life; skin to skin.  Alright guys, I know what you are thinking.  Don't get your girlfriend hypothermic just to use this solution.  You need to be a bit more suave and a little less reckless if you want the relationship to grow!

But lets assume you may not have that bag.  You might need to depend on nature to survive.  Even with the bag, how can you stay dry?  Now what?

Take the time to learn about rubbish huts, lean-to shelters, snow caves, and the like.  They all are similar in that they turn water or snow and create insulating walls.  It takes longer to make these shelters than one would think.  That is why it is imperative to start early--right after you have stuffed your clothes with lots of dry, itchy stuff.   The key is to create a dry, insulated space, and fill it with dry, light stuff, like leaves.  Crawl into that pile of leaves and pull the door closed.  One can survive and even be warm in rather crude piles of leaves and sticks in incredibly cold weather.  Just a note….  Lean-to shelters are great for warm rainy nights and not a lot else.  If it is cooler than warm, you will need a shelter that is more substantial.

We will expound more on shelters in future blogs.  But in short, think small, dry, insulating, light, and breeze-proof.  A stack of pine boughs against a log covered and stuffed with leaves will save your life.  Really.  When it is critical, don’t try to build a palace.  Make a small shelter that will stop the wind and turn the rain.  Fancier shelters can be made in the sunshine. 

And the number one rule is to be DRY.  Moisture sucks away body heat.  If you are soaked, then you will have to get dry clothes, even if those clothes are just a scratchy, THICK pile of leaves.  Stay dry.  Get dry.  Nude and dry is better than wet.  Number two rule for staying warm is to drink plenty of water and eat high energy foods.  Staying warm burns a lot of fuel.  But if you don't have these at hand, get dry and sheltered and worry about the food in the morning.  The cold will get you before hunger or thirst.

Okay, okay, I can hear you asking, “What about fire?!”  I leave fire out of the survival equation.  Unless you have a shelter to catch and keep the heat from a fire, it really offers little value for staying warm.  Sure, you can roast one side while freezing the other, getting soaked to the bone, struggling to keep the fire going all night long with wet and wetter wood.  What is the point of that?  Make a shelter rather than a fire, and stay dry and insulated.  You can build a fire for fun in the morning.  Use it to signal for help or cook up a trout, but don’t depend on fire to keep you warm. 



Wilderness survival:

Attitude
Shelter
Getting found
Water
Food
Comfort

There is more to come as the series continues.  One unmentioned key to wilderness survival is to get out there in the woods and practice skills when the weather is fine and all is fun and games.  Build several types of shelters.  Be familiar with materials that can be used for insulation.  Be accustomed to the time it takes to build a shelter.  Learn to plan ahead and work with nature’s bounty.

Do any of you have a survival shelter idea or experience to share?  Please post a comment.  You might save a life!




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