Hypothermia occurs when the body loses heat faster than it can produce it. Whatever your outdoor adventure may be, the risks increase in winter when you exercise and sweat in cold weather. Less than adequate clothing becomes damp against the skin. Body temperature drops.
For the individual sportsman or the person hiking with family and friends. For group leaders like those we see in our Wilderness First Aid training. This article gives you ten things to think about as you focus your attention on prevention.
Because if you are unfortunate enough to get hypothermia in the middle of nowhere, you probably lack the resources and time needed to fix it there. Prevention is Key.
I have spent many years exploring the outdoors during the winter months. Once the snow hits the ground, it opens up a world of opportunity to see what can't be seen at any other time of year.
There is nothing quite like it. The once leaf-clogged trees obstructed the mountain and river valley views, but not anymore. Hiking through river valleys and up the sides of mountains means you can now appreciate the terrain on a more immediate level.
Another great advantage of fresh snow is the ability to track and follow animal movements. A favorite past-time of mine is to catch trail cam footage of animals during the winter months. After observing and tracking their movements for several months, I've succeeded in capturing images of a lynx and her kittens.
Engaging in this kind of activity means heading out in less than desirable conditions. Being prepared and knowing how to avoid the dangers that are ever present becomes an essential skill.
It is also a time when people venture out when they should not, and that can be dangerous,. Even deadly.
In February of 2017, I was heading back from a hike and came across a car that looked like it had drifted off the road into a snow bank. It was about minus 15 F with wind chill and I was not about to leave someone stranded.
Pulling over to the side of the road I saw the vehicle was empty. And when I looked closer, footprints were heading away from the car - and away from the nearest farm. It would easily be seen by anyone standing in that spot who turned to look in the opposite direction.
This was not a typical place to park and go for a walk. Even with good visibility and across an open field I could see no sign of whoever belonged to this vehicle. Immediately I notified emergency services because we had no idea what we would find if anything.
The police arrived and we began to follow the tracks. The snow got deeper and about a mile and a half in the police radioed for snowmobile backup. We kept going and approached the beginning of the tree line along the top of the river valley.
About a hundred yards down the incline we found a man, alone and disoriented, lying in the snow. In his late 40's and reasonably fit, he was dressed in jeans, a light leather jacket, and a balaclava. He was hypothermic. We got him to the top of the valley in time for the snowmobile to show up and whisk him off to the hospital.
I found out later he had been in a fight with his wife and wanted to get some air and clear his head. It almost cost him his life.
1. Check the Weather Before You Go
This is where preparation starts. Anytime you head outdoors the weather plays a central role in the experience. During cold weather this is even more true. The human body is particularly vulnerable in the cold. Assess what you will be up against before you head out.
We have never before had the advantage of so many resources for understanding the weather from both a macro and micro perspective. Long term forecasts that range out to weeks. And hour by hour accounts of the changes you can expect throughout a day. Satellite imagery.
Weather conditions change rapidly. Know all you can before you go, but plan and prepare for every eventuality.
2. Pay Attention to the Wind Chill
Many people only look at air temperature when checking the weather. In cold weather the wind speed is of equal importance. The combination of wind speed and air temperature has a cumulative impact that exceeds any simple reading of the temperature.
And if you are wet? The combination of these three factors increases the speed with which you will lose temperature.
The fourth factor is time. The longer the time you are exposed to the first three factors - the more likely it is you will run into trouble.
3. Avoid Hypothermia
Hypothermia occurs when the body loses heat more quickly than it can produce it. Whenever the ambient air temperature is cooler than the core temperature of 98.6F you can be at risk for hypothermia. [i]
Granted that it is not common to observe hypothermia when the temperature is in the 80's.
The lesson here is: Do not discount the possibility at any temperature. Especially when the perfect storm of factors we are addressing in this article combines to create the potential. Exertion and resulting perspiration, windy conditions. Fatigue, dehydration and lack of nutrition. A patient who lies down to rest losing heat via conduction to the ground beneath them . . .
4. Wear the Correct Clothing and Carry the Right Equipment
Your clothing is your ultimate protection against the weather and the conditions. It's your individualized environment that you carry around with you.
The gold standard is to layer your clothing so that you best manage your body temperature. Unzip. Vent. Remove layers as you exert yourself, warm up and begin to sweat. Replace those layers the moment you stop and start to cool off. Do it again. And again.
Being systematic. Forcing that discipline on yourself and setting an example for others. Removing and replacing, again and again, is the key to managing your moisture when exerting yourself in cold weather exercise.
Wear clothing made of fabric that wicks moisture away from your body. Avoid cotton clothing at all costs. Cotton will kill you. It absorbs moisture and increases your risk for hypothermia. [https://skyaboveus.com/climbing-hiking/Why-Cotton-Will-Kill-You] Your underlayer should be long sleeved so that if you must expose it, even for a short time, your skin is not directly exposed to the air.
What is the most effective pair of gloves? The second pair. Because if the first becomes wet, it's worthless. What is true for gloves, is true for socks, and is true for all your clothing. Have a backup plan. Make sure you can change yourself into a dry person should you fall into the water when crossing an ice-covered stream.
Always keep a spare change of clothing back at the car.
5. Protect Your Head, Hands, and Feet
Pay particular attention to your extremities. In cold weather body heat escapes most rapidly from these areas.
As a leader, be observant of the choices people make. A person removes their gloves to accomplish a task, only to shove them in a pocket and forget to put them back on. Set the example for others of uncovering these parts only when you must, and then covering them back up.
Thermal packs can contribute to the comfort of your extremities.
6. Don’t Head Out if You’re Not Physically Prepared For It
This is not the time to be heading out on a hike for the first time. Know what you are capable of and know you have the physical condition to tackle the terrain ahead of you. This is the wrong time to find out the hard way.
A trail you are comfortable with at any other time of year will present unique challenges in the winter. Drifts of deep snow that drain your energy. The need to alter your route around sheets of ice and other obstacles.
If you are not prepared to give it everything you have - both mentally and physically - you can find yourself in some pretty serious trouble. Whether it’s snow, ice, cold, wind or a combination of the above these conditions will make the simplest trail a much tougher challenge.
7. Prevent and Avoid Exhaustion
You might be in great shape, but if you are not well-rested you are susceptible to exhaustion. The fatigued person is predisposed to hypothermia. [https://www.semanticscholar.org/paper/Exertional-fatigue%2C-sleep-loss%2C-and-negative-energy-Young-Castellani/13ed92fc2ea6c0353e8e6e3bfce12ecfc535a3ed] Get a good night’s sleep and avoid late night binges and alcohol consumption the evening before. Alcohol consumption increases the risk of hypothermia. [https://www.mayoclinic.org/diseases-conditions/hypothermia/symptoms-causes/syc-20352682]
On the trail, pace yourself. It’s best to take more frequent but shorter 2-5 minute breaks. You measure out your exertion to cut your risk for exhaustion. You manage and limit your perspiration. Don’t push yourself to the point where you require a more extended break as this can cause your body temperature to drop more than you want.
And remember, fatigue is among the earliest signs of cold-related illness.
8. Provide Your Body with Good Nutrition
When you exert yourself in cold weather, you should expect to consume at least 25% more calories than usual. Your nutrition intake fuels your body's ability to produce energy and heat. [https://www.hprc-online.org/articles/peak-nutrition-in-cold-weather]
To prepare for your event eat well the day before and have a good breakfast before you hit the trail. Snack at all rest stops and maintain your calorie intake all day. Continuous snacking avoids the hunger that forces you to take longer breaks. Pack food that works with this strategy.
9. Always Stay Hydrated
Hydration is always important but often neglected in cold weather. When it’s cold we tend not to drink as much as we should.
People engaging in strenuous exercise drink only 2/3 the water the body really requires. If you wait until you are thirsty it's too late. You are already partially dehydrated. [https://www.bcm.edu/news/sports-medicine/thirsty-you-are-already-dehydrated]Drink early, drink often and drink more than you think you need. Water, of course. Avoid alcohol, coffee, tea, and other drinks that have a diuretic effect.
If you are hiking in extreme cold make sure your water does not freeze. If your water freezes you are in big trouble. Even if you are capable of making a fire to thaw it, you will be forced to stop for longer than is safe or wise. Especially in the short days of winter.
If your water freezes, fire is your best option to thaw it, so carry it in a metal water bottle. To avoid freezing your water keep it well insulated. Bury it in the center of your pack, wrapped in some of your spare clothing.
10. Remember Your Safety Gear and Sunscreen
An emergency can occur at any time but when it happens in extreme cold, the inherent danger can escalate rapidly.
Because there are more factors in play. Because of the increased risk to rescuers. Because of the increased challenge of extraction. Consider that winter is peak season for Murphy's Law.
Be prepared. Be more prepared. Carry adequate safety gear with you to make sure you can deal with any situation. An emergency heat source, first aid, a communication plan, cordage and tarp and more are all worth carrying.
Don't forget the sunscreen! If the sun is shining you can burn and blister. Snow is reflective and the sun can prove treacherous.
11. Location, Location, Location
Know your surroundings at all times! Because the cold presents tough challenges, and especially if things go wrong.
It is essential that you always know where you are and how far you are from your vehicle or major roads. Maps (yes! the real old fashioned kind!) and GPS are vital if you are in an area which does not have a signal for your mobile device.
Invest some time, ahead of time, in logistics. Know where the closest points of entrance and egress are at all points along your route.
Be extra-prepared if you will be out of communication range. Make sure someone back home knows your travel plan, has a copy of the map, and knows when to expect your return.
Winter outdoor adventure is a fantastic way to enjoy the wilderness. Get outside and make the most of the activities you love, but make commons sense decisions and get home safely.
[i] Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition. Available from: https://www.ncbi.nlm.nih.gov/books/NBK331/