Travel Reference
In-Depth Information
ularly the absence of a need to void after a night's sleep. They certainly can recognize the
deepyellowororangecolorofconcentratedurineindicativeofdehydration.Whenvoiding
into snow, orange “snow flowers” are an ominous sign.
Food is needed for physical activity and heat production. Eating small amounts of food
at frequent intervals helps prevent depletion of energy stores during the day. Some exper-
ienced outdoor recreationalists seem to be munching almost continuously and often have
developed mixtures of nuts, dried fruits, candies, and other high-calorie food. Such mix-
tures are sold as gorp or trail mix.
Ina survival situation, experience has demonstrated that foodis one ofthe most import-
ant ingredients of success. Any source of food, even wild animals such as birds or rodents,
whichmayhavetobeeatenuncooked,ispreferabletothefatigueanddepressionthatresult
from not eating and can contribute significantly to hypothermia.
Clothing
Clothing for cold climates must not only protect from the cold but also must be able to
compensate for changes in environmental temperature and for heat production by exercise.
The most flexible cold weather clothing systems are composed of three layers: an inner
layer (underwear), one or more middle insulating layers, and an outer windproof (and per-
haps water repellent) shell. The middle and outer layers can be opened or removed when
environmental temperature or heat production increases. Additional insulating layers can
be added as the temperature falls or the person becomes inactive.
Inamultilayeredclothingsystem,eachsucceedinglayermustbeslightlylargerthanthe
onebeneath.Ifthelayersarethesamesize,theouterlayerscompressthedeeperlayersand
reduce their insulation value.
However, the outer layer must not be too large. It must be snug enough to be warmed
by the wearer's body so that its inner surface temperature does not fall to the dew point.
If that occurs, moisture collects on the inner surface and wets the insulating layers, greatly
reducing their effectiveness.
Sweating must be avoided. Sweat moistens the clothing, greatly reducing its insulation
value, and more heat is lost as the perspiration evaporates. Outer layers must be opened or
taken off as soon as activity begins, not after the individual has become hot and begun to
perspire.Theselayersmustbeputbackonorclosedassoonasactivityceases,notafterthe
individual has become cold and requires more heat to rewarm.
Clothing Materials
Nothird-partytestingfacility,suchasUnderwritersLaboratory,existsforclothing.Buy-
ers are at the mercy of advertising agents serving the manufacturers and sellers. The most
reliable indicator of a fabric or garment's performance is its persistence in the marketplace
for two to three years or more.
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