Joe and Amy are authors of The Survival Medicine Handbook: The Essential Guide For When Help Is Not On The Way and Alton’s Antibiotics And Infectious Disease: The Layman’s Guide To Available Antibiotics In Austere Settings. They also run doomandbloom.net which is an excellent source for austere medical knowledge.
The environment plays a large role in your success as medic in survival settings. If you don’t take weather conditions and other factors into account, you have made the environment your enemy, and it’s a formidable one. Different areas may pose special challenges. If you live in Miami, you might be treating a lot of people with heat stroke. If you live in Siberia, you’ll be treating a lot of people with cold-related exposure. In many places, you’ll be at risk for both, depending on the time of year.
Illness related to cold temperatures is known as ‘Hypothermia”. Normally, the body core ranges from 97.5 to 99.5 degrees Fahrenheit (36.5-37.5 degrees Celsius) when taken orally or rectally. Rectal temps tend to be slightly higher than oral, and oral temps slightly higher than skin readings, such as those taken in the armpit. Hypothermia begins when the body core drops below 95 degrees.
The body loses heat in various ways:
Evaporation – Perspiration (sweating) from physical exertion or other reasons releases heat from the body core.
Radiation – the body loses heat to the environment when the ambient (surrounding) temperature is below the core temperature. For example, you lose more heat if exposed to an outside temperature of 20 degrees F than if exposed to 80 degrees F.
Conduction – The body loses heat when its surface is in direct contact with cold temperatures, as in the case of someone falling from a boat into frigid water (think “Titanic”). Water, being denser than air, removes heat from the body much faster.
Convection – Heat loss where, for instance, a cooler object is in motion against the body core. The air next to the skin is heated and then removed, which requires the body to use energy to re-heat. Wind Chill is one example of air convection: If the ambient temperature is 32 degrees F but the wind chill factor is at 5 degrees F, you lose heat from your body as if it were actually 5 degrees F.
The body, when it is exposed to cold, kicks into action to produce heat. It does this by muscle actions as the core cools. Muscles shiver to produce heat, and are a warning that you need to warm up. As hypothermia worsens, more symptoms will become apparent.
Aside from shivering, the most noticeable symptoms of hypothermia will be related to mental status. The person may appear confused, uncoordinated, and lethargic. The victim’s speech becomes slurred and they often will appear uninterested in helping themselves.
All this occurs due to the effect of cooling temperatures on the brain; the colder the body core gets, the slower the brain works. Other organs begin to shut down, and the victim loses consciousness. Any unconscious person you find exposed to cold weather is hypothermic until proven otherwise.
Cold-related tissue effects also includes local damage, such as frostbite. Frostbite affects areas like fingers, toes, nose, earlobes, and even lips. Sometimes called “Frostnip” or “Chilblains” in early stages, it begins as numbness, pins and needles sensations, and redness. Blistering may occur.
If not warmed, the skin turns progressively white and waxy, then blue, and, finally, black, a condition known as “gangrene”. Gangrenous tissue is dead and unsalvageable in survival settings, and may require debridement (the removal of dead tissue) or amputation.
Prevention of Hypothermia
An ounce of prevention is worth a pound of cure, and many cases of hypothermia can be prevented. To prevent hypothermia, you must anticipate the climate that you will be traveling through, including wind conditions and wet weather. Condition yourself physically to be fit for the challenge. Travel with a partner if at all possible, and have enough food and water available for the entire trip.
Remember the simple acronym C.O.L.D. This stands for: Cover, Overexertion, Layers, and Dry Cover. Dress appropriately for the weather. Protect your head by wearing a hat. This will prevent body heat from escaping from your head. Instead of using gloves to cover your hands, use mittens. Mittens are more helpful than gloves because they keep your fingers in contact with one another. This conserves heat.
Overexertion. Avoid activities that cause you to sweat a lot. Cold weather causes you to lose body heat quickly; wet, sweaty clothing accelerates the process. Rest when necessary and use rest periods to self-assess for cold-related changes. Pay special attention to the status of your elderly or juvenile group members. Diabetics are also at high risk.
Layers. Loose-fitting, lightweight clothing in layers allow a thin layer of warm air between and do the best job of insulating you against the cold. Use tightly woven, water-repellent material for wind protection. Wool or silk inner layers hold body heat better than cotton does. Some synthetic materials, like Gore-Tex, work well also. Especially cover the head, neck, hands and feet.
Dry. Keep as dry as you can. Get out of wet clothing as soon as possible. It’s very easy for snow to get into gloves and boots, so pay particular attention to your hands and feet.
Immediate measures must be taken to reverse the ill effects of hypothermia. Failure to act quickly may lead to organ failure and death. Important measures to take are:
Get the person out of the cold. Transport to a warm, dry location. If you’re unable to move the person out of the cold, shield them as much as possible. Be sure to place a barrier between them and the cold ground.
Monitor breathing. A person with severe hypothermia may be unconscious. Verify that the patient is breathing and check for a pulse. Begin CPR if necessary.
Take off wet clothing. If the person is wearing wet clothing, remove them gently. Cover them with layers of dry blankets, including the head, but leave the face clear.
Share body heat. To warm the person’s body, remove your clothing and lie next to the person, making skin-to-skin con- tact. Then cover both of your bodies with blankets. Some people may cringe at this notion, but it’s important to remember that you are trying to save a life. Gentle massage or rubbing may be helpful, but vigorous movements may be traumatic.
Give warm oral fluids. If the affected person is alert and able to swallow, provide a warm, nonalcoholic, non-caffeinated beverage to help warm the body. Alcohol does not warm you up; instead, it expands blood vessels and actually hastens the loss of heat from the body core.
Use warm, dry compresses. Use a first-aid warm compress or a makeshift compress of warm (not hot) water in a plastic bottle. Apply compresses to the neck, armpit, and groin. These areas will transport heat to the body core more effectively than placing warm compresses on the extremities, which sometimes worsens the condition.
Avoid applying direct heat. Don’t use hot water, a heating pad or a heating lamp directly on the person. The extreme heat can damage the skin, cause strain on the heart, or even lead to cardiac arrest.
The concern of anyone stranded in the cold, whether it’s in the wilderness, an urban environment, or a vehicle is to find the warmest shelter available. In the post-collapse city, many abandoned buildings will provide a refuge from the wind and, perhaps, fuel to build a fire. A vehicle can serve as its own shelter.
In the forest, a “tree well” shelter can be constructed out of the snow. A tree well is the sunken area around the trunk in very deep snow. This area is relatively easy to excavate and, if the tree has low-hanging branches, should provide some protection from falling snow. Look for natural barriers nearby that may serve as windbreaks, but beware of slopes where you may be exposed to drifting snow or avalanches.
The space you dig out should be small, as small shelters take less effort to keep warm than large ones. Pack your snow “walls” well, so that they can retain heat better and support a makeshift roof. Place evergreen boughs and debris on the floor to protect you from the cold ground. Then, add some on top to make a roof. Tarps or solar blankets may be used for this purpose, but winds might easily blow them off. Tie rocks to the corners as weights.
If you make a fire, be sure to have ventilation holes in your shelter. Entrances and ventilation holes should open at a 90 degree angle to the prevailing winds.
Let’s say you’re stuck in a stalled car on the road in a blizzard. Stay in the vehicle as, thanks to your body heat, the temperature in the vehicle is warmer than outside; in addition, you have protection from the wind. Leaving the vehicle might disorient you in driving snow.
If the motor runs, turn it on for only about 10 minutes each hour for heat. Although the heater helps, wet snow can block up your exhaust system and cause carbon monoxide gas to enter the passenger compartment. You’ll need fresh air, so crack a window on the opposite side from where the wind is coming. If you’re in a group, huddle together as best you can to create a warm pocket in the car.
Your muscles produce heat involuntarily by shivering, but you can rub your hands, put them in your armpits, or otherwise keep moving to achieve the same goal.
The Winter Survival Car Kit
There are a number of items that you should always have in your car, especially in cold weather. These are meant to keep you safe if the unthinkable happens and you’re stranded without hope of rescue. A full set of camping supplies would be useful to keep if you have space in your car, but there are some items that are especially important:
- Wool blankets (for warmth; wool can stay warm even if wet)
- Spare sets of dry clothes, especially socks, hats, and mittens.
- Hand warmers or other instant heat packs (activated by shaking, they’ll last for hours)
- Matches, lighters, and fire starters to manufacture heat Flashlights and candles (keep batteries in backwards until you need them to extend life).
- Small multi-tool with blade, screwdrivers, pliers, etc.
- Larger combination tool like a foldable Chinese Army shovel (acts as a shovel but also an axe, saw, etc.)
- Sand or rock salt (to give traction where needed) Tow chain or rope
- Starter cables (for jump starts)
- Water and food (energy bars, MREs, dehydrated soups, candies) Baby wipes (for hygiene purposes)
- A medical kit and medications
- Tarp and duct tape (brightly colored ones will be more visible and aid rescue)
- Metal cup or thermos (to melt snow, make soup, etc.) Noisemaker (whistle) to signal for help
- Cell phone and charger, weather radio
It should be noted that some of the above materials, such as starter cables, are most helpful in normal times when rescue resources are available.
Winter can be harsh, but with some planning and supplies, it’ll be a bump in the road, but not the end of the road. Act quickly to help a victim of hypothermia, and you’ll save a life.