From: Ventura County Search & Rescue /         Ed Petru  1/1/85                       Updated  10/03/02 6:33 PM

           additional notes/comments: Mike Fink, Larimer County Search & Rescue / Colorado

Subject: P.R. Handout on Layering

 

THE BASICS OF LAYERING =====================

 

LAYER 1/underwear

The layer of clothing closest to your skin should trap insulation dead air space for warmth close to your body, and "breath" well to permit the escape of body moisture, thereby preventing the condensation and collection in clothing of moisture that can cause serious chills and lead to Hypothermia.

Mesh underwear and wool long johns are excellent choices for your inner clothing layer.  Warm even when wet wool dries from within, wicking moisture away from the skin.  Mesh or "fishnet" underwear worn under a shirt or sweater traps pockets of insulation dead air while freely breathing away moisture.  Those who do not like the texture of wool against their skin can wear double - layer wool/cotton underwear or synthetic fishnet underwear as a buffer between their skin and outer layers of wool clothing.  The effectiveness of mesh underwear can be increased by wearing a lightweight turtle­neck over it.

Cotton underwear cannot be recommended since cotton absorbs moisture and loses its insulation ability when wet, actually contributing to heat loss by conduction.

LAYER 2/wool or synthetic fleece

Wool's unique abilities to provide warmth even when wet, and to dry from within, wicking moisture away from the skin, make wool the natural choice, even an imperative, for your second layer of clothing. Synthetic(not cotton) fleece provides similar characteristics with typically less weight.

Wool is an excellent insulator and is strong, abrasion resistant, naturally water - repellent, and naturally elastic, permitting great freedom of movement.

A lightweight or midweight wool shirt worn with trousers or knickers over long underwear will usually be warm enough for the more strenuous periods in cold - weather activities.  The adjustable collar, cuffs and front of the shirt permit fine - tuning of ventilation for comfort.

Knickers are the best choice for activities requiring maximum freedom of movement, while trousers provide more protection from heavy brush and severe weather.  Suspenders are better than a belt because they permit greater freedom of movement.

LAYER 3/down or synthetics

While Layers 1 and 2 may be warm enough for more strenuous activity during moderately cold weather, rest periods and extreme cold require additional insulation, provided most efficiently by down and synthetic materials or fiberfill.

A parka or vest of down or synthetics provides maximum insulation with a minimum of weight or bulk by entrapping a thick layer of insulating dead air space within its fibers.  Down and synthetic or fiberfill garments "breathe" well and are very light­weight and compressible, permitting greater freedom of movement when worn and easy storage when not needed.  When increased activity or warmer weather temporarily eliminate the need for a down or fiberfill parka or vest, it can be compressed to a fraction of its size for easy carrying in your pack.

Remember that the homeostasis process sends warmth to your limbs when your body core, or torso, is kept warm.  For this  reason, in  moderately cold weather a vest may suffice instead of a parka, and down trousers, though available, are needed in  only  ex­tremely cold weather, or in activities involving a minimum of physical exertion.

LAYER 4/water/wind shell(breathe-ability)

 

Wind robs heat.  Even a seemingly gentle breeze can radically reduce the effective air temperature to a fraction of the station­ary air temperature.

The  outer  shell  of your layered clothing system should be able to keep out wind and water while  allowing  body  moisture  to "breathe"  away.   Unless your outer shell breathes, you'll get wet from body moisture condensation no matter how much  rain  it keeps out.

Mountain  parkas of water - repellent 60/40 cloth, polyester/cotton blends, or waterproof Gore-Tex are  light-weight,  windproof and  "breathe-able", making them an excellent choice for use as the outer shell of your layered clothing system.  In  a  downpour, 60/40 and polyester/cotton mountain parkas can

be  augmented with a lightweight, loose - fitting poncho of plastic or coated nylon, which can be worn to protect your  pack  as well as your body.  Gore-Tex mountain parkas need no additional rainproof layer.

Your  mountain parka can be stored compactly in your pack until wet or windy weather calls for its use.  In the coldest  weather it  can  be worn over both the wool and down or synthetic layers for maximum warmth.  In moderately cold weather,  the  mountain parka  can greatly increase the warmth of your wool layer.  Excellent Windbreakers in mild weather, mountain parkas add to  your outdoor comfort, safety, and performance through all four seasons of the year.