Weather
and Living Things
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Lesson 4
Hypothermia: The Cold as a Killer
Introduction | Invitation | Exploration | Explanation | Taking Action | Conclusion
In previous lessons, we
have explored problems that are related primarily to an
increase in temperature in various regions of the
world. But despite the possible warming of our planet,
cold weather conditions provide some of the most dangerous
and deadly situations for man and beast alike. In this
lesson we will discuss the dangers that come from exposure
to the cold and learn about ways to minimize these
threats.
Hypothermia may be a new word for you, but it is an
effective term for describing the rapid mental and physical
collapse that occurs when the inner core of your body begins
to drop in temperature. Hypothermia is caused by prolonged
exposure to the cold and the effects can be intensified by
wetness, wind, and exhaustion. The signs of
hypothermia include uncontrollable shivering, memory loss,
confusion, slurred speech, and apparent exhaustion.
Surprisingly, hypothermia is the number one killer of
outdoor adventurers and campers.
To introduce this lesson, try to think of the one time in your life when you felt the coldest. After thinking about it, go to the Eco-Connections Project Forum and write a paragraph or two to describe this experience. It will interesting to see how the experiences of the Russian and American students differ in this regard.
Objectives
Upon completion of this lesson, you should be able to describe the nature, causes, and symptoms of hypothermia and discuss ways to minimize hypothermia in order to survive a cold weather threat.
Materials
Acetone or rubbing alcohol, glass.
Invitation
Even though hypothermia is the leading cause of death among outdoor adventurers, most of the people who die from hypothermia are those that are caught unexpectantly in some form of winter storm. Hypothermia often attacks when motorists become stranded in their cars for extended periods during a blizzard or winter storm event. If you became stranded, you might think that the best thing to do is to keep the car running and roll the windows up tight. To check out what you can really do to maximize your chances of surviving, check out the following link and then answer the questions below.
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Questions:
1. What key things do you need for a winter disaster supply kit?
2. What is the difference between a winter storm warning and a blizzard warning?
3. Name 3 key things that you should do if get stuck in your car.
Exploration
If you do get caught outside in a storm, the wind can be a major threat to your survival. The term "wind-chill" is usually used to refer to the detrimental effect of moving air on exposed flesh. The wind chill is based on the rate of heat loss from exposed skin caused by the combined effects of wind and cold. As the wind increases, heat is carried away from the body at an accelerated rate and this acts to drive down body temperature quickly. For instance, with a 27.8-kph (17 mph) wind and a temperature of -10 degrees C, the equivalent wind-chill temperature is -23 degrees C. This means that your body will lose heat at the same rate that it would if the temperature was -23 degrees C and the wind was calm.
The table below gives the wind-chill factors for various wind speeds at a temperature of -15 C.
Table
1: Effect of Wind Speed on Equivalent Chill
Temperature
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If you expect to survive being stranded outside, you must
act wisely to limit your exposure and prevent
exhaustion. Realize that the moment your body begins
to lose heat faster than it produces it, you are potentially
in big trouble. As you sense the heat leaving your
body, you may exercise to try to stay warm and/or your body
starts to shiver involuntarily in order to preserve the
normal temperature in your vital organs. The problem
with these actions is that they drain you of the critical
energy reserves that you my need to
survive.
To limit your exposure, you should try to:
1.STAY DRY. When clothes get wet, they lose about ninety
percent of their
insulating value. Wool loses less as does many of the new
synthetics. Cotton
and wet down are worthless.
2. COVER ALL EXPOSED BODY PARTS
3.BEWARE OF THE WIND. If necessary prepare a windbreak or
lean-to for
protection from the wind.
4.UNDERSTAND THE COLD. Although extremely cold
air can be deadly,
most hypothermia cases develop in air temperatures between
30 and 50
degrees. Most outdoor enthusiast simply can't believe such
temperatures
can be dangerous. Don't fatally underestimate the danger of
being wet
at such temperatures.
Note:To demonstrate the cooling power of an evaporating
liquid place your
finger into a cold beaker of rubbing alcohol that has been
provided by
your teacher. As you feel the energy leaving
your finger as the alcohol
evaporates, you can begin to appreciate how this process
could act to
accelerate hypothermia in people who get
wet.
Explanation
Finally, it is important that your beware of the likelihood
of exhaustion. Recognize that exposure greatly reduces your
normal endurance. You may think you are doing fine when the
fact that you are exercising is the only thing preventing
your going into hypothermia. In many cases you
should build a shelter or wind-break and see if you can get
a fire started. IF you can, put rocks around it to absorb
and reflect the heat.
If you do become
exhausted and you're forced to stop then you're in big
trouble due to the following reasons:
1.Your rate of body heat production instantly drops by fifty
percent or more.
2.Violent, incapacitating shivering may begin
immediately.
3.You may slip into hypothermia in a matter of
minutes.
To learn more about
hypothermia, you can explore the following web
sites:
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Taking Action
In
addition to protecting yourself from the cold, you never
know when you might find someone who is hypothermic and it
need of help. If you are out camping or deep in the
woods and you find someone who is in trouble, the following
actions are suggested:
1.Get the victim out of the wind, rain, or
snow.
2.Strip off all wet clothes.
3.If the victim is only mildly impaired:
Give him/her warm drinks. (only small
amounts)
Get him/her into dry clothes and a warm dry sleeping
bag.
Well wrapped warm (not hot) rocks or canteens placed in the
crotch
and under the arms anywhere the main arteries are close to
the surface
of the skin, will hasten recovery.
4.If the patient is semi-conscious or
worse:
Try to keep him/her awake. (Do not give hot liquids by
mouth.)
5.Build a fire to warm canteens and rocks for warming the
victim.
6.Transport the victim as soon as possible to the closest
hospital for monitoring.
It takes a very long time to warm the inner core.
DON'T DELAY!
Conclusion
In this lesson, we learned that hypothermia can result from
prolonged exposure to the cold and the effects can be
intensified by wetness, wind, and exhaustion. We also
discussed the symptoms of hypothermia including
uncontrollable shivering, memory loss, confusion, slurred
speech, and apparent exhaustion. Finally, we learned
that although hypothermia is a leading cause of death among
outdoor adventurers, certain steps can be taken to
effectively reduce the risks.
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