Tuesday, November 17, 2009

Extreme Cold Survival

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It's that time of year again, the cold weather is setting in, hunting season is upon us, and many of us will be venturing outdoors again for fall and winter adventures. But with the falling mercury comes the risk of exposure to deadly temperatures. Humans are a tropical species. It is only through our brain power and tool making ability that we were able to fashion insulating garments and settle in temperate and arctic zones. When faced with extreme cold, humans simply cannot survive for long without the proper tools.

What are the keys to surviving in very cold conditions? Cold temperatures alone are not the only factor to consider. Others conditions that will exacerbate the loss of body heat, such as wind and moisture must be taken into account. Certain situations can quickly turn deadly in the cold. Finding yourself stranded on the side of the road may simply be annoying in warmer months, but could be deadly in the winter. A winter adventure could easily become very dangerous if you venture out unprepared.

Moisture and Snow
Staying dry is incredibly important in extremely cold weather. The human body loses heat 25 times faster when exposed to cold water than when exposed to cold air. Even when your body is not immersed in water, it cools at an incredible rate from any moisture on the skin.

Moisture on the skin evaporates quickly in the low humidity of cold weather, causing an evaporative cooling effect on the skin. When working outside in the extreme cold, take care that you do not begin to sweat. If the exertion of hard work makes you begin to get hot, remove some layers of clothing to cool off. Sweating in the extreme cold can be a death sentence, for once you stop exerting yourself, you are left drenched in moisture that will quickly evaporate and wick away an enormous amount of heat.

If you are not properly equipped, never venture out into the snow. In addition to the immense exertion it takes to navigate deep snow without snowshoes, snow presents a very real hazard from the moisture that it leaves after melting from your body heat.

Be aware of falling or blowing snow. In high winds, snow is blown about and collects in pockets, boots, parka openings, virtually anywhere it can find a crack, crevasse, or opening in your cold weather clothing. Falling and drifting snow can collect around vehicles and shelters, blocking doors and exits and entombing any occupants inside. If you are sheltering in a vehicle or a building, you will need to frequently clear snow that has collected around doors and exits to prevent an accumulation from blocking the door.

Snow weighs on average between 5 and 10 pounds per cubic feet. While this may not seem like much at first glance, snow accumulation can quickly overwhelm the load-bearing strength of many structures, especially structures not built to support a static load. Most structures built in areas that routinely receive snowfall have a rated snow load. Those structures that are not load rated must be kept clear of accumulation.

Wind Chill
Wind chill is one of the gravest threats of cold weather. In still air, your body actually heats up the air surrounding it, forming a little bubble of warmer air around you. Wind whips that warm air away and rapidly cools the body. To make matters worse, wind enhances the evaporative cooling effects of moisture on your skin. Even in temperatures that don't seem deadly, high winds can quickly leave you in a dire predicament. The table below illustrates just how cold it actually feels at different wind speeds, and where frost bite begins to set in at different wind chill temperatures.

windchill chart

There are a number of medical conditions that can be brought on by extreme cold. Probably the most well known is hypothermia. Hypothermia occurs when the body is no longer able to maintain sufficient body heat and the core temperature falls below 95 degrees Fahrenheit. Symptoms of hypothermia include exhaustion, confusion, delerium, bright red or pale skin, memory loss, and uncontrollable shivering (or, in advanced hypothermia, no shivering at all despite a very low body temperature).

Frostbite and Frostnip
When your core temperature begins to fall, the body reacts by keeping blood flow restricted to essential organs in the core and sacrifices blood flow to the extremities. This loss of blood flow means that extremities such as fingers, toes, hands and feet do not get enough warm blood flow to maintain tissue at a healthy temperature. The result is frostnip, and eventually frostbite. Frostnip is an early warning sign of frostbite, and is characterized by pale, cool flesh and numbness or loss of sensation in the affected areas. At the extreme, frostnip can actually result in the freezing of outer layers of the skin. Caught early, the damage is not permanent and simply results in the damaged skin peeling off similar to a 1st degree burn. Left unchecked, frostnip will progress into frostbite, where the tissue temperature falls below freezing and ice crystals begin to form in tissue cells. The ice crystals destroy the cellular structure, killing the affected tissue. Superficial frostbite causes the skin to turn black when rewarmed, but the damage, though painful, is not permanent. The damaged skin eventually peels off and is replaced by new tissue. Deep tissue frostbite is a serious condition, usually resulting in the loss of the affected tissue.

Frostnip and frostbite can be difficult to detect on yourself, so use of the buddy system is essential. Keep an eye on your buddy, and have them keep an eye on you, looking for the initial symptoms of frostnip. Should frostnip be detected, simply warm up the affected areas either by moving to a warmer area, or by protecting and insulating the area of concern. When dressing for the cold, pay close attention to the size of your protective clothing. Layers of socks can help insulate the feet, but boots will need to be a size or two larger than normal. Otherwise, the pressure of the additional sock layers inside of the boot will constrict blood flow and actually increase the risk of frostnip or frostbite.

The treatment for almost all cold injuries is warmth. One of the fastest methods to rewarm a victim of the cold is immersion in a warm (not hot!) bath. Frost bitten limbs can be immersed in warm water as well. Care should be taken not to burn frost-nipped or frost-bitten limbs. Damage to affected tissues reduces or eliminates any sensation, so the victim may not be able to tell if a source of warmth is too hot and causing pain and damage to the affected area.

Combating the Cold
The body burns a lot of calories when trying to stay warm. It is not unusual to burn through more than 7,000 calories a day in the field, so it is important to feed your body's furnace.
MREs are a great addition to any emergency survival kit. Most MREs are designed to be calorie dense and provide 1,500 to 3,000 calories per pack. Staying hydrated is also critically important. Water acts as an insulator, making your body more resistant to temperature changes. When staying hydrated, don't eat snow or drink cold water. The hydrating effects of the snow and water are offset by the cold temperatures. Try to drink lukewarm or hot liquids. These will hydrate you and keep you warm. Water bladders filled with warm water or broth can also act as a hot water bottle and keep you warm when worn close to your base layer of clothing underneath a parka.

Protection In The Wilderness
It's a common situation bandied about by survivalist types: You're somehow stranded miles from nowhere in freezing weather and deep snow. What do you do to survive? Besides cutting open a Tauntaun and keeping warm in it's entrails as Luke Skywalker famously did in the movie Star Wars, The Empire Strikes Back, one commonly mentioned solution is the snow cave. Inuit Eskimos have long used the insulating properties of packed snow and ice when constructing their igloos, why then shouldn't the same principles be able to keep you safe from the elements in a survival situation?

The answer of course is that you can stay safe and somewhat warm in a snow cave, but naturally it's not quite as easy as that. As valuable as they are as a survival method, snow caves can also prove quite deadly for a variety of reasons. A poorly constructed snow cave can collapse, trapping you beneath layers of snow and ice. Insufficient airflow can cause carbon dioxide to build up, and this can be even more dangerous if a candle or lantern is burning inside the cave. Finally, falling snow accumulation can block the entrance and exit to the cave, entombing you inside.

When building a snow cave, work slow and methodically, taking care not to over exert yourself. Sweat can be deadly in the cold, so if you begin to get warm, remove some layers of clothing. It's amazing how fast you can cool down by simply removing an insulated hat or cover.

Proper planning and construction of your snow cave is of paramount importance. Poorly designed entrances allow cold drafts in and eliminate the insulating properties of the cave. Snow caves should have a domed roof with ventilation holes poked in the top. The entrance should be below the main floor, igloo style, so that the heat stays in the cave. The walls should be very thick at the base and form a domed arch for structural support.

Other options for shelter in the cold include rocks, caves and ledges, as well as a hastily constructed lean-to.

Equipment When Adventuring in Extreme Cold
Ideally, you should have a well-stocked pack with good survival equipment and gear, including a well-built, 4-season tent. A well-stocked pack for your outdoor winter adventure should include the following:

1. Sun Block
The sun's harmful rays bounce off of the bright white of the snow. Wraparound sunglasses are necessary to block out harmful UV rays from damaging your eyes. You can actually go "snow blind" and literally get a sunburn on your retina. Such burns can be severe and painful, so wear your shades! In a pinch, if you do not have proper eye protection, a strip of c loth wrapped around your head "blindfold-style" with small slits cut in it can protect your eyes from harmful rays while allowing you to still see by peering through the slits. Additionally, you should have SPF 35 or higher sun block to protect your face and exposed skin from sunburn.

2. Light and Emergency Signal
Always carry at least one small flashlight and spare batteries. Many things can cause your adventure to take longer than you thought, and such lights are invaluable in allowing you to find your way back to camp or the trailhead if you find yourself out after dark. Lights are also invaluable for signaling rescuers at night, should the need arise. In addition to a light, pack an emergency signal such as a flare gun or signaling mirror. A whistle is also useful for alerting someone to your location, and can easily be attached with a lanyard to your pack. High-powered green lasers also make an excellent signaling tool, as their beam is usually visible even when viewed indirectly.

3. First Aid Kit
This one should be a no-brainer, but always carry a first aid kit with you when you're out in the wilderness. When away from civilization, that kit may be the only way to keep yourself or someone else alive while you get back to a modern medical facility or wait for rescue. Kits should include bandages and ointments for cuts and scrapes, as well as over-the-counter drugs for pain management, but don't neglect supplies for trauma. A tourniquet can be used to stem blood flow for up to four hours without permanent tissue damage. Consider including a blowout kit with a c lotting agent for serious wounds, especially if you will be out hunting or using firearms. This list is not all inclusive, but should be used as a starting point for your personal first aid kit which may need specific items such as prescription medications, glucose for diabetics, or an Epi-Pen and antihistamines for those with severe allergies.

4. Emergency Shelter
It doesn't have to be a $1,000 four season tent (though that never hurts) but you will need some sort of emergency shelter. Something as small as a two-man, ultralight tent will work in an emergency. We offer a disposable emergency survival tent that is excellent for emergency shelter. It packs up very small and is easily carried. If you want something a little better, this Eureka Timberline tent is a good all-around camping tent. It packs up small and weighs only 10 lbs, so it won't weigh down your pack.

5. GPS
Maps and compasses are great, but they are no substitute for a good handheld GPS unit. You don't have to spend a ton of money to get a quality unit, Garmin units are available from just $137.95, and should you find yourself lost in the cold, that's money well spent. Maps and a compass should also be carried, but learning to use them well takes practice. Learn to use both a compass and a GPS system in conjunction with a topographical map for the best results.

6. Extra Clothing
A simple slip and fall could leave you soaked in the freezing cold. Water and moisture are probably the biggest contributor to hypothermia in an extremely cold environment. Having a change of clothes could literally save your life. At a minimum, you should carry an extra set of base layer clothing: wool socks, long underwear, pants, shirt, and a pullover fleece or wool sweater.

7. Fire
Always carry a couple of lighters, or some waterproof matches and a fire-starting system that you have practiced using. When you're alone and cold in the wilderness is no time to try to learn fire-starting skills. Practice with your equipment beforehand so that when it is cold and snowing or raining you will be able to quickly and easily start a warm blaze.

8. Tools (knife, hatchet, shovel, and specialty tools)
Carry specialty tools for your showshoes or skis, as well as a multi-tool such as a Leatherman. A fixed blade or hatchet, and a shovel are also indispensable items you should carry. If you are hiking a glacier or other icy terrain, learn how to use and carry an ice axe.

9. Food and Water
This is another one that should seem obvious, yet time and again people head out into the cold without emergency rations or water. Should you find yourself lost or unable to get back to shelter and civilization, that food and water can give you a few days rations. Food helps the mind as well. When lost and frustrated, simply sitting down to have a drink and a small snack boosts morale and helps you to think positively. Throwing a couple of MREs in your backpack can prove to be a lifesaver.

10. Communication
Cellphones, or at least an EPIRB or SPOT Messenger should be considered a necessity in this modern day and age.

Cold Weather and Traveling
The most common place you may find yourself stranded in the extreme cold is stuck in a vehicle stranded on the side of the road. Icy spots, snow drifts, mechanical difficulty, any of these can leave you alone and without help on the side of a cold and desolate highway. What can you do if you find yourself stuck in such a predicament? Obviously the first answer is to make sure that you are properly prepared.

When traveling through areas where the weather is extremely cold, you should always pack a cold weather survival kit in your vehicle. What you pack in your emergency kit will vary from person to person depending on your situation, but there are some things that should be in every kit. Each kit should contain some basic survival and emergency gear, in addition to a first aid kit and tire chains if appropriate. I keep my kit in a rubber tote, although duffel bags or other large bags work well too. Your basic kit should contain blankets or sleeping bags, water, food, a flashlight, flares or emergency triangles, jumper cables, and an ice scraper or brush. Whenever you travel in severe winter weather, always take a mobile phone and a portable phone charger. If you still have room in your kit, I find that tire chains, a tow rope, a shovel (such as our compact shovel 36565), and bag of sand or granite (granite chips are usually available at your local gravestone manufacturer) are lifesavers for getting you un-stuck from deep snow or treacherous ice. Other items may include hand warmers or chemical heaters such as the ones often included with MRE kits.

If you find yourself stranded in your vehicle in the cold, the first thing to do is to stay calm. Signal your distress by raising your hood and tying something brightly colored to your radio antenna. Retrieve your cold weather survival kit, and anything else you need, from the trunk of your car or bed of your pickup truck and move it to the passenger compartment so that you don't need to make multiple trips outside in the cold to get individual items from the kit.

Don't leave the engine running. If you are stuck in a snow drift, or even just stopped on the side of an icy road, carbon monoxide from the exhaust can build up in the passenger compartment. If your engine is still functioning, run it for no more than 10 minutes an hour to heat up the interior. Make sure that a window is cracked an inch or so, and that the exhaust pipe is clear of any snow or other obstructions to reduce the risk of carbon monoxide build up.

Keep your cellphone or other battery-powered emergency devices as warm as possible by making sure that they are near your body in an inside pocket, not in an outside parka pocket or on the dashboard or console of the vehicle. Batteries lose their charge as much as 10 times faster when they are below 32F. By keeping your cellphone warm you will extend the battery life.

Tactical Considerations
Military, Police, or any type of tactical operator working in extremely cold conditions will have a number of other things to consider.

Extremely cold weather causes gear and equipment to function differently. Many lubricants become solid or gel in the cold. Military manuals advise eschewing CLP in favor of more cold tolerant lubricants such as LAW (Lubricant, Arctic Weather) when lubricating firearms and other equipment in conditions below zero degrees Fahrenheit. Battery-powered equipment should be kept warm, or be used with special cold weather batteries.

Consideration must also be given to the mobility and dexterity of an operator in an extremely cold environment. Cold weather clothing inhibits dexterity. Gloved hands make it more difficult to manipulate controls, and heavy garments make quick and accurate movement more dificult. Equipment may need to be altered to accomodate some of these problems. Larger trigger guards on weapons, like our Magpul MIAD modular pistol grip kit for the AR-15 with mission adaptable grips are perfect for gloved hands. Hoods and eye protection limit peripheral vision, so operators in the cold really need to keep their heads on a swivel.

Police have additional concerns they must address when dressing for extreme cold. Coats and jackets can impede access to duty belts and weapons. Some coats are designed with a slit in the side to allow access to a service pistol, but officers should practice drawing their weapon as the garment can still snag a weapon as it is being drawn.

Enjoy the Cold
The cold weather brings with it all manner of opportunities to enjoy the outdoors and winter sports. Just because the mercury drops doesn't mean that you are stuck indoors. Go outside and have fun! But by all means, be prepared and take the necessary precautions against the extreme cold.

1 comment:

  1. When your body is losing heat faster than it can make it. Symptoms include uncontrollable shivering, exhaustion, delirium, drowsiness, memory loss, slurred speech and bright red skin. This is a dangerous condition because the symptoms themselves can easily prevent self-diagnosis by the victim.
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