Another important topic when out in the cold is foot care. How do you keep your feet warm, dry, and happy?
Keep your feet dry. This is perhaps the most important way you can help yourself. Wet feet stay colder longer and are more prone to frostbite and blisters. If your socks are soaked through, change them for a dry pair and stuff the wet ones in your jacket or in your sleeping bag. If you’ll be in particularly snowy conditions, gaiters can work wonders for keeping snow out of your boots. While a waterproof gaiter will stop water from coming in, it will also prevent it from getting out as well. If you have particularly sweaty feet, you will need to take this into consideration if gaiters are required by using a lighter set, bringing extra socks, or perhaps forgoing gaiters altogether, depending on the conditions and the particulars of your feet. Single leather boots will breathe much better than double-layer plastic boots, reducing foot sweat, and potentially keeping your drier. However, truly cold conditions dictate a double boot, so plan accordingly.
Keep your socks dry. This definitely goes along with keeping your feet dry, but is important in its own right. In general, I have three pairs of socks with me in the backcountry. One pair is on my feet, one pair is probably drying out, and one pair is staying dry in some safe, protected place just in case the current pair on my feet gets soaked. Any time socks are not on your feet, if they aren’t dry, they should be getting actively dried out, either in your jacket or in your sleeping bag (in both cases, your body heat inside the aforementioned gear is a necessary part of the equation). I also make sure to change my socks at least daily, even if they aren’t particularly wet just to make sure they stay as dry as possible.
Start your day with warm, dry boots. Again, this will help you keep your feet dry (noticing a pattern here?) In general, your boots should be pretty warm during the day since your feet will be in them. The biggest challenge is starting with warm boots in the morning after your feet have been out of them all night. This is particularly problematic as your boots are very good insulators. They keep warm things warm, but they also keep cold things cold. If you start the day with cold boots, you will likely have persistent cold feet throughout the day.
With double boots, the usual solution is to sleep with your boot liners in your sleeping bag, drying them out and warming them up. If you have single boots, things are a bit trickier. One solution is to only use single boots on day trips when you’ve got some place warm to go at the end of the day. However, you can usually get away with single boots for a few nights by placing them on top of your sleeping pad and under the foot of your sleeping bag at night, or even placing the entire boot in the foot of your sleeping bag if it’s really cold. Another trick is to warm your boots over the stove in the morning as you’re making breakfast, melting snow, etc. However, this allows for the possibility of steam to creep into your boots, making them warm but also moist. Depending on your feet and the conditions, this can be okay, or it can be disastrous. I recommend experimenting with this technique to see how it works for your before relying on it.
Wear proper boots. When you’re out in the cold weather, ensuring that your boots are properly laced will go a long way to keeping your toes warm. Over-tight boots restrict circulation, reducing the flow of warm blood to your extremities and cooling your feet. Keep your laces as loose as possible to maintain functionality. Similarly, the boot should be properly sized for your foot and your socks should not be too thick for the boot. Initially, you may have to start with a thinner sock, progressing to thicker socks over the life of the boot as the boot gets “packed out” by your foot.
Keep your boots warm and dry while out in the cold. The biggest point here is to avoid standing in the snow. Certainly, if you’re in the snow, this is hard to avoid and would be impossible in practice. However, if you’ll be in one place for a little while, take the effort to pack down the snow a bit before settling in, keeping the snow under the insulating rubber of your boot soles instead of packed entirely around your foot. Even when I’m just stopping to relieve my bladder, I take the extra 5 seconds to pack down a standing platform instead of standing post-holed in knee-high snow. My feet thank me for it.
Also, recognize the chilling effect crampons have on your boots. Strapping cold, highly-conductive metal to your feet is going to work wonders for cooling your toes. Use the least-technical crampon effectively suited for the task and only put the crampons on when you need; take them off when you don’t. For example, micro-spikes will have a much smaller cooling effect than 12-point technical ‘pons. Of course, speed or convenience may override your concerns about cold feet, but if that’s the case you’re probably exerting enough that the crampons won’t have much of a cooling effect. Use your judgment.