Clothing & Heat Loss

By

David Cronenwett  2007

As autumn rolls around, backcountry hunters begin looking forward to our journeys into the mountains.  We should take care to prepare ourselves for unforeseen situations involving rapid changes in the weather, since fall can and frequently does, morph into winter and back again from day to day. 

The biggest problem that autumn and early winter poses to people is hypothermia, which is the insidious and potentially deadly lowering of the body's core temperature.  Ironically, hypothermia is less likely to be a problem in winter-proper because most people dress warmly enough to expect it.  It is more of an issue during the other three seasons. 

Still, a high-stress survival scenario, one which may find you having to get through a night or two in frigid cold without a sleeping bag, could easily push your body into a precariously cold state.  The body loses heat via convection (wind action drawing heat away), conduction (direct contact with a cold object), radiation (an un-insulated body in a cold environment) and evaporation (moist skin conducts heat away from the body 240 times faster than dry skin).  A simple test for the early signs of hypothermic incapacity is to touch the thumb to the little finger.  If there is any difficulty whatsoever, you must either exorcise vigorously or immediately light a fire, the latter being more desirable.  If you are alone, you may quickly become unable to revive yourself beyond this point of early-stage hypothermia.

Any of the cold-related maladies can make firemaking difficult or impossible.  Be sure to read the Jack London classic, To Build A Fire, then try this simple experiment:  with a fire already going, take off your gloves and allow your hands to become thoroughly numb.  Next, try to make a substantial fire inside of five to ten minutes.  If you succeed, consider yourself lucky.  If you fail or give up, run back to your other fire and remind yourself to never let your hands deteriorate to such a state!

Dehydration is a common and debilitating condition to the recreationist regardless of the season.  All bodily functions including the thermoregulation system, rely on adequate water reserves. You will become much colder if you do not drink enough water to always urinate clear liquid.  You may also develop gnawing headaches, digestion problems and become lethargic.  None of these symptoms are conducive to making it through a cold weather survival situation.  The body's thirst mechanism should not be used to gauge your hydration.  It is best to drink hot tea or water throughout the day, which is why a pot of some kind is an absolutely integral part of the winter survival kit. 

The importance of clothing in survival scenarios and indeed, for all outdoor pursuits, must never be underestimated.  Clothes insulate us from cold and protect us from rain, snow and abrasion.  People who otherwise would have perished in the wilderness have been known to squeak by because they were adequately dressed.  In cold conditions especially, you must wear or carry enough clothing for the worst conditions to be expected.  

The layering system, one that emphasizes several thin layers over fewer heavy ones, is well known by most people.  However, in the past twenty years or so, the clothing material of choice, namely polypropylene fleece and other synthetic fabrics, has supplanted the traditional option of wool.  The reason for this is almost exclusively fashion and advertising related, since these products are simply not withstanding the test of time.  Recently however, more people are rediscovering the amazing qualities of wool and more companies are manufacturing excellent, high-performance products. 

First, wool is a natural, renewable fiber that can be sustainably produced and will eventually biodegrade.  Compare this to the petroleum intensive nature of fleece products that will last for centuries in the landfill.  In my opinion, most synthetic outdoor garments are vastly inferior to their traditional wool or cotton counterparts.  When working and living around open fires and woodstoves, having a wardrobe of plastic clothes can be simply dangerous.  I have seen expensive parkas and fleece pullovers riddled with "spark holes", and witnessed the gruesome melting and outright combustion of gloves, hats, pants and other items made of similar materials.

Wool and canvas are much less flammable and are easier to repair when damaged.  Wool lacks the disturbing quality of some synthetics to hold on to body odor forever, no matter how many times you launder them.  Companies like Ibex have a line of excellent, durable and non-itchy garments for a wide range of outdoor pursuits including mountaineering and backpacking. Their Merino wool long underwear line is absolutely to die for. 

The so-called waterproof-breathable fabrics that comprise the bulk of raingear today will never live up to its own advertising.  Hard, sustained use in the wilderness, as opposed to weekend outings will destroy these products in short order.  Though they may technically breathe, they cannot do enough of it to prevent moisture buildup (from perspiration) and eventual saturation of your inner layers, especially when you are working strenuously.  A good wool coat may keep you as dry or more so than a Gore-tex parka.  If you are interested in staying truly dry, by impermeable rain gear, seek shelter and wait out the weather, since physical activity in any rainwear will soak you from within. 

Having said all this, I recognize that many people use synthetic clothing and there is a place for it.  We would only like to recommend that individuals who spend a lot of time in the wilderness to give wool clothing a try, you may be surprised by the results.