Survival - Winter Time Camping.pdf - survival(3) - T-e-T

Winter Time CampingOCF Winter Time Camping

Exploring the wilderness in winter is a wonderful experience. You are far from

the crowds, in a hushed tranquil world of white. Whether gliding through a glade

of maple trees on cross-country skis, hiking up a ridge on snowshoes, or ice

climbing, winter can be a spectacular time of year.

At the same time you must realize that this environment can be extremely

dangerous. It takes proper trip planning, experience, and the right equipment to

travel safely in the winter environment. If you aren't aware of the hazards you

can be at great risk. This article will help you understand how to travel in the

winter wilderness. The greatest dangers in the winter environment are

hypothermia and frostbite.

The Following Topic's will give you a little insite on what is needed and

required for Your Winter Time Adventures

Trip Planning

Personal Equipment

Food

Winter Water

Winter Shelters

Leave No Trace Camping in Winter

Winter Travel

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Trip Planning

Planning a trip in the winter means spending a good deal of time researching

areas and conditions to determine where, when, and how the trip will work. All

of these factors will interact to determine what your daily pace and mileage can

be.

Goals for the trip

Route - will you be on a trail of off trail, or a mix

Snow level - shallow or deep

Snow quality - powder, packed, breakable crust, or variable

Trail - breaking trail or on a broken trail

Mode of travel - will you be hiking, snowshoeing, or skiing

Elevation changes - going up may be very slow while coming down may be very fast

Strength and experience of group

Group size

Keeping all these factors in mind, set up a Time Control Plan for your trip.

Keep in mind that everything takes "twice" as long in the winter (setting up

camp, breaking camp, cooking, going to the bathroom, etc.). Look at your

proposed route for potential campsites for each day. Also look to see where you

could camp before your planned site if you can't make it. Know what your

emergency and bail out options are if conditions deteriorate or you have

problems. Talk to area rangers about permits and camping restrictions. Find out

about snow levels, avalanche danger, safety of ice crossings, etc.

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Personal Equipment

The essence of staying warm in the winter is having the proper clothing layers

and knowing how to use them effectively.

Heat Loss

The body basically acts as a furnace, producing heat through chemical reactions

and activity. This heat is lost through conduction, convection, evaporation,

radiation, and respiration. As physical activity increases so does heat

production and conversely as activity decreases so does heat production. The key

to keeping warm is to add insulation to the body.

Insulation

The thermal insulation of clothing is proportional to the thickness of the dead

air space enclosed. Dead air is defined as any enclosed unit of air that is

small enough that natural convection currents would not arise in it. Such

currents have been detected in units as small as 2 millimeters in diameter. The

dead air next to the skin is heated up by the body and provides a layer of

warmth around the body. The clothing is not what is keeping you warm it is the

dead air. This is because the denser a material the faster it can transfer heat

through conduction, the density of air is obviously minuscule compared to a

piece of a fabric. The "clo" unit was developed to provide a measurement of

insulating effectiveness. One clo is roughly equal to the insulating value of an

ordinary wool business suit. Each inch of thickness of conventional insulating

materials (wool, pile, down) provides a theoretical value of about 4.7 clo or a

practical "in use" value of 4.0 clo.

The Layering Principle

The key to providing this dead air space is through having a number of layers of

clothing. Each layer provides a certain clo value of dead air space. This allows

you to add or shed layers to increase or decrease your accumulated dead air

space as the temperature changes and/or as your activity level changes.

Remember, your body is the heat source, the clothing layers only serve to trap

the heat and slow down your heat loss to the cold environment. If you have too

much clothing on, you will overheat and start to sweat. You need to find the

proper heat balance between the number and types of layers and your activity

level.

Why not just have lots of layers on and sweat? Heat loss from a wet surface can

be up to 25 times greater than a dry surface (due to the higher density of

water). If you sweat and get soaked, you will lose heat much more quickly

through evaporation of the water. Also you are loosing an incredible amount of

water through sweating since the air is so dry. Too much water loss leads to

dehydration which significantly increases the risk of hypothermia. So you want

to control your layers so as to be warm at the activity level you are in but not

sweating profusely.

Thus, traveling in the winter is a constant process of adjusting your layers to

keep comfortable. This means having a number of layers you can add or subtract

and allowing for versatility within layers. Convection may account for the

greatest amount of heat loss under most conditions. In order to properly

insulate, you need to have an outer layer that is windproof.

Another general rule is that the efficiency of clothing is proportional to the

diameter of the body part it covers. Thus a given thickness of insulation added

to your trunk will be more thermally efficient than the same thickness added to

your arm or leg. It will also help maintain that body core temperature. This is

why vests work well to maintain body heat. There is an optimal thickness of

insulation for each body part. Beyond that the added bulk tends to be more of a

hindrance in movement than the added insulation is worth.

Example=Have you ever noticed that your hands feel colder after putting on a

thin pair of gloves? This is because when insulation is wrapped around a curved

surface, the cross-sectional area of the insulation through which the heat may

flow is greater as is the surface area from which the heat may be lost. This

means that the total insulation efficiency of a given thickness progressively

decreases as curvature sharpens over a surface. In addition, small cylinders,

such as fingers, show a paradoxical effect. The addition of a thin layer of

insulation actually increases heat loss until a thickness of about 1/4 inch is

reached. This heat resistance gains as additional thickness is added. However,

added thickness beyond 1/4 inch increases warmth very little in proportion to

its thickness. This is one reason that thin gloves don't keep your hands

particularly warm.

Clothing Materials

Some of the different types of materials for winter clothing and insulation are

discussed below.

Wool - derives its insulating quality from the elastic, three-dimensional wavy

crimp in the fiber that traps air between fibers. Depending on the texture and

thickness of the fabric, as much as 60-80% of wool cloth can be air. Wool can

absorb a fair amount of moisture without imparting a damp feeling because the

water "disappears" into the fiber spaces. Even with water in the fabric wool

still retains dead air space and will still insulate you. The disadvantage to

wool is that it can absorb so much water (maximum absorption can be as much as

1/3 third the garment weight) making wet wool clothing very heavy. Wool releases

moisture slowly, with minimum chilling effect. Wool can be woven in very tight

weaves that are quite wind resistant. An advantage to wool is that it is

relatively inexpensive (if purchased at surplus stores). However, it can be

itchy against the skin and some people are allergic to it.

Pile or Fleece fabrics - is a synthetic material often made of a plastic

(polyester, polyolefin, polypropylene, etc.). This material has a similar

insulative capacity as wool. Its advantages are that it holds less water (than

wool) and dries more quickly. Pile is manufactured in a variety of different

weights (thicknesses) offering different amounts of loft and insulation. This

allows for numerous layering possibilities. The disadvantage of pile is that it

has very poor wind resistance and hence a wind shell on top is almost always

required. Versions of pile are available that have a middle windproof layer.

Polypropylene and other Hydrophobic fabrics - polypropylene is a synthetic,

plastic fiber which offers dead air space and a fiber which cannot absorb water.

The fiber is hydrophobic so it moves the water vapor away from the source (the

body). Polypropylene layers are extremely effective worn directly against the

skin as a way of keeping the skin from being wet and reducing evaporative heat

loss. As the water moves away from the body it will evaporate, but each

additional millimeter of distance between your skin and the point of evaporation

decreases the amount of body heat lost in the evaporative process. Some fabrics

rely on the chemical nature of the fiber to be hydrophobic. Others fabrics use a

molecular coating the achieve the same end.

Vapor Barrier Systems - another way to stay warm in the winter is through vapor

barriers. The body is always losing water through the skin even when we are not

active. This loss is known as insensible perspiration and occurs unless the air

humidity is 70%. This insensible perspiration goes on at the rate of nearly half

a quart every 24 hours. Since it takes 580 calories per gram to turn liquid

water into water vapor, heat is continually lost through insensible perspiration

as well as through sweat from any activity. A vapor barrier is a clothing item

which is impervious to water thereby serving as a barrier to the transportation

of water vapor. When worn near the skin it keeps water vapor near the skin.

Eventually the humidity level rises to the point where the body senses a high

humidity level and shuts off insensible perspiration. This prevents evaporative

heat loss and slows dehydration.

Vapor barriers should not be used directly against the skin because any

evaporation of moisture directly at the skin surface leads to heat loss. Wearing

polypropylene or some other hydrophobic layer between the skin and the vapor

barrier allows the moisture to be transported away from direct skin contact.

There is no doubt that vapor barrier systems are effective for some people in

some conditions. The issues you must consider before using a vapor barrier are

activity level, amount you naturally sweat, and "moisture comfort." If you are

not active, such as when using a vapor barrier liner at night in a sleeping bag,

the system will work well. A vapor barrier sleeping bag liner will typically

permit you to sleep comfortably in temperatures 10 - 15 degrees colder than in

the bag alone. However, some people find that they are not comfortable with the

level of moisture in the bag and fell clammy. If this interferes with sleeping

it may be a problem, better to have a better insulated sleeping bag. Vapor

barrier liners for sleeping bags also help in another way. In cold conditions,

the moisture from your body escapes upward through the bag, when reaching the

cold outside of the bag it condenses into liquid or event frost. Over a number

of days this moisture level in your bag increases. If you can't dry out the bag

it will slowly get heavier and heavier as it holds more water. With a down bag,

this moisture can actually soak the feathers and cause the bag to loose

significant amounts of loft (dead air space), thereby reducing it's

effectiveness.

When you are active, like snowshoeing, and you are wearing a vapor barrier such

as a vapor barrier sock, you must carefully monitor how you sweat. If you are

someone who sweats a lot with activity, your foot and polypropylene liner sock

may be totally soaked before the body shuts down sweating. Having this liquid

water next to the skin is going to lead to increased heat loss. If you don't

sweat much, your body may shut down perspiration at the foot before it gets

actually wet. This is when the vapor barrier system is working. The important

point is that heat loss comes from water changing state from a liquid to a gas.

Liquid water next to the skin leads to significant heat loss. Water vapor next

to the skin does not. You must experiment to determine if vapor barrier systems

will work for you.

Polarguard, Hollofil, Quallofil and others - these are synthetic fibers which

are primarily used in sleeping bags and heavy outer garments like parkas. The

fibers are fairly efficient at providing dead air space (though not nearly as

efficient as down). Their advantages are that they do not absorb water and dry

fairly quickly. Polarguard is made in large sheets. Hollofil is a fiber similar

to Polarguard but hollow. This increases the dead air space and makes the fiber

more thermally efficient. Quallofil took Hollofil one step further by creating

four "holes" running through the fiber.

"Superthin" fibers - Primaloft, Microloft, Thinsulate and others - the principal

behind these synthetic fibers is that by making the fiber thinner you can

increase the amount of dead air space. For example, take an enclosed space 5

inches wide and place 2 dividers into that space, each 1 inch thick. You have an

effective air layer of 3 inches. If you take the same 5 inch space and divide it

with 4 dividers, each 1/4 inch thick you now have an effective air layer of 4

inches. You have gained one inch. Under laboratory conditions a given thickness

of Thinsulate is almost twice as warm as the same thickness of down, however,

the Thinsulate is 40% heavier. Thinsulate is made in sheets and therefore tends

to be used primarily for outer layers, parkas and pants. New materials such as

Primaloft and Microloft are superthin fibers that are close to the weight of

down for an equivalent fiber volume. They are now being used in parkas and

sleeping bags as an alternative to down. They stuff down to a small size and

have similar warmth to weight ratios as down without the worries about getting

wet.

Down - feathers are a very efficient insulator. They provide excellent dead air

space for very little weight. The major problem with down (and it can be a major

problem) in the winter is that down absorbs water. Once the feathers get wet

they tend to clump, and lose dead air space. Using down items in the winter

takes special care to prevent them from getting wet. For example, a vapor

barrier sleeping bag liner in a down bag will help the bag stay dry. Down is

useful in sleeping bags since it tends to conform to the shape of the occupant

and prevents convection areas. Down is very compressible, which is an advantage

when putting it into your pack but also realize that your body weight compresses

the feathers beneath you and you need good insulation (foam pad, etc.)

underneath you, more so than with a synthetic bag. Some people are allergic to

down. The effectiveness of a down bag is directly related to the quality of the

feathers used. Since down is made of individual feathers, sleeping bags are

garments must have baffles sewn in to prevent the down from shifting in the bag

which would create cold spots.

Radiant Barriers - some portion of body heat is lost through radiation. One

method of retaining this heat is through use of a reflective barrier such as

aluminum. This is the principal used in "Space Blankets" and is also used in

some bivy sacks and sleeping bags.

Cotton is basically useless in winter time. It wicks water, but unlike

polypropylene, cotton absorbs this moisture and the water occupies the space

previously occupied by dead air. This means a loss in dead air space, high

evaporative cooling, and a garment that is almost impossible to dry out.

The Body and Clothing

Head - because the head has a very high surface to volume ratio and the head is

heavily vascularized, you can lose a great deal of heat (up to 70%) from the

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