A forum member who attended the Ontario hang last weekend asked me to repost something I wrote for another forum on the subject of winter footwear and how to keep one's feet warm while winter camping in deep cold conditions. I'm re-posting it here.
Avoid high-tech winter boots
Modern, high tech winter boots are fully waterproof on the outside and have multiple absorbing layers on the inside to wick water away from your foot. These work superbly until they are saturated or until you stop moving around. At that point, they become moisture traps, turn freezing cold, and you lose heat by conduction through water in your boots; a very rapid way of losing heat. You will absolutely get cold feet very soon after you stop moving from moisture build-up inside your boots, and moisture will have built up just from the normal activity of snowshoe travel and making camp. These boots are great for day trips where you can remove them and let them dry out at night in a dry, heated house, but when you're camping, they will freeze solid overnight. They are miserable to put on in the morning, and if you forget to open up the lacings before you go to sleep, it can be a struggle to just get into them in the morning. They thaw out only by virtue of your feet bleeding heat into them. In effect, they cease being insulators and become heat-loss enhancers.
Drying winter boots over a fire is much harder than people imagine. It takes a very long time, uses a lot of wood, and they never dry thoroughly so you never have truly dry boots for the rest of the trip. They'll warm up alright and feel great when you put them on after they've been over a fire, but will cool down in short order and you'll have the same problem you started with. And that's assuming the weather is conducive to building a large warming fire. In bad weather (rain, high winds, blizzards, etc) you may be unable to start or sustain a warming fire long enough to significantly reduce the wetness of your boots Save these types of boots for day hikes, snowshoeing, or one-nighters. They are unsuitable for winter camping in sub-freezing temperatures.
Wool socks are best. They insulate well, retain some of their insulating properties when very damp, vent moisture away from your foot (but not out of your boot) and, because they breathe, can be night-dried in your sleeping bag while you sleep; either worn, or just resting on you inside your bag. I like to wear two pairs of wool socks in deep cold. When it's less cold, I wear a thin synthetic sock that wicks moisture away and a heavy wool sock over that. Avoid cotton socks or cotton blend socks as cotton does not wick moisture away from your skin and they won't dry out overnight. I would have liked to have said something about the vapour barrier sock method, as some people swear by it, but I've never tried it.
Wear pac boots
They are rubber on the lower part with nylon or leather uppers that can breathe a bit. Leather uppers are reputed to breathe better, but I've never owned a pair and can't confirm that. What makes pac boots so suitable for winter camping is that they have removable felt liners which can be dried out while wearing a second dry pair. Spare liners are sold separately. Get the liners made of felted wool, if you can, but synthetic liners work. Without dry liners to change into, they are no better than any other boot. Your damp liners will night-dry in your sleeping bag while you sleep and be warm and dry by morning so that you never have to put a foot into an icy boot. Pac boots vary greatly in price, but there are many types to choose from. They are bulky and ugly, don't appeal to the urban outdoor fashion market, and so typically sell for less than modern high-tech winter boots. Some boot companies won't sell spare liners, but they are quite interchangeable between brands. Pac boots are commonly available in secondhand and discount stores such as Good Will, the Salvation Army stores, and Value Village. You can often find a good pair there for less than the price of a spare liner. You can also realistically dry your liners over a fire because they are just felted material and aren't encased in rubber or some other waterproof material. I should add that I'm a cold-camper who sleeps in igloos and I have never needed to dry my liners over a fire; night-drying has always worked for me.
The logic of the pac boot (as well as felt-lined mukluks, or felt-lined rubber boots) is that the felt liner absorbs moisture readily and wicks it away from your sock. Good liners wick so well that your liners can sometimes be very wet on the outside, mildly damp inside, and your wool socks (and feet) almost completely dry. At day's end you just remove the soaked liner and replace it with a warm dry liner the following morning. The wet pair can be dried over a fire or night-dried inside your sleeping bag. The lower part of a pack boot is made of rubber, making it suitable for wet snow, slush, or rainy conditions, while the nylon or leather upper allows some (not much) of the moisture in the liner to evaporate during the day.
On the down side, pac boots are ugly, heavy, bulky, and because one needs to get them in sizes larger than one would normally buy for one's foot size to accommodate heavy socks and still have toe-wiggling room, they feel particularly heavy. But, they are cheap compared to high-tech boots. High-tech boots are much, much smaller, lighter, but they are costly and eventually, the permanent inner absorbent liner gets compressed, losing it's absorbent capacity, and once the lining's absorbency is compromised, the boots are not even warm enough for long day hikes. With pac boots or felt-lined mukluks, old liners are just discarded and replaced for a fraction of the cost of a new pair of boots, making them even more economical because you don't need to replace them often.
Sizing of pac boots
Pac boots need to be much bigger than what you'd normally wear. They have to be able to accommodate your foot, plus two heavy wool socks and have room left for wiggling your toes. I'm a size 10.5 and I wear an 11.5 or 12. A constricted foot or immobile toes will lead to poor circulation and cold feet. If you can find pac boots that have a very high toe box, get them. With this sort of boot, there is room enough inside to add another layer of insulation below your foot by buying or cutting out a felt insole that you put underneath the felt liner. This extra insole significantly reduces heat loss through conduction when you're standing or sitting.
Smoke-tanned mukluks (such as those sold by Steger) with felt liners, in conjunction with rubber boots and liners is another good option. Smoke-tanned mukluks are very expensive to make or to buy, however, they are lighter, more comfortable, they breathe and vent foot moisture directly to the outside, so moisture is not trapped inside. They are also flexible soled and this means your feet and toes are free to move, bend, twist and this increases circulation to the feet. As with pac boots, they are used with felt liners, but they don't get nearly as wet by the end of the day. Mukluks are not waterproof, so you also need to bring along a pair of cheap, regular rubber boots (with felt liners) for those mild days when the snow is wet, it's rainy, or when you need to cross slush-covered frozen lakes. I have never camped in mukluks myself, but I know people who have, and I have worn them in winter as daily footwear as a teen so can attest to their comfort and breathability firsthand.
Regular rubber boots with felt liners
This is the poor man's pac boot. It works. It's what I used as a kid when I began winter camping. They are not the most comfortable thing to walk in, and you will wet your liners much sooner because there's no nylon or leather upper to permit some moisture venting, but bring 2 spare pairs of liners and you will manage just fine.
These are your camp slippers to be worn outside around camp or inside your shelter. They breath and are flexible. These are not cheap and vary in quality. They will keep your feet warm and it's a good idea to get out of your boots and into these whenever possible so your felt liners don't absorb more moisture than necessary. You can even sleep in them. They are lightweight and they pack well. They also make good little pillows at night.
Warming your feet up during the day
If your feet get cold, you have to do something about it right away. It never just goes away. If you don't act, it will worsen. Cold feet will not only make a winter camping trip miserable, it is dangerous, as it can rapidly compromise both your ability and even your willingness to walk. Below are suggestions based on my own experiences on how to keep feet warm when you feel cold creeping into them:
Increase blood flow to your feet
Get moving. Get into your snowshoes and trudge up a steep hill for 5 minutes or until your heart rate is elevated. Jog in your snowshoes for 5 minutes. Go collect firewood briskly. Grab your snow shovel and start building snow furniture such as a sitting bench, wind wall, waist-high cooking surface, etc. Keep going until your feet warm up and then very gradually slow down. Paradoxically, you will want to shed layers of clothing as soon as you feel yourself warming up. You want to increase blood flow, not work up a sweat.
Keeping feet warm when not moving:
When doing a chore that requires sitting or when sitting down to eat, your feet can often get cold from contact with the cold ground or snow (conduction), inactivity (lessened blood flow to the feet), and wind blowing against your feet (convection).
- To counter heat loss by conduction, put some insulation between your boots and the cold ground or frozen/packed snow. A small square of closed-cell foam or reflextex to rest your feet on is ideal to reduce conductive heat loss through the bottom of your feet.
- To counter heat loss by convection and radiation when seated, stick your feet in deep snow. It sounds crazy, but it works. Snow is an insulator and will greatly reduce convection and radiation. To appreciate how effective an insulator snow is, consider the method for keeping your water bottles from turning into ice overnight is to drop them into snow and cover them with snow.
- If your socks or liners have become too damp, change into your dry socks and liners.
- If you have chemical heating packs, you can slip one into each boot for temporary relief, but you mustn't rely on these.
The keys to warm feet are lots of food for your metabolic furnace, drinking plenty of water, good quality sleep, activity, roomy boots permitting blood circulation, insulation against heat loss, and minimizing moisture in your footwear.
I know this was a bit of a long and tedious read and will be old hat to many here, but for those who are contemplating winter camping or beginner winter campers, it can make the difference between a miserable trip and one that leaves you wanting to go out again.
Hope this helps,