At -20°C, the world is pretty normal. It’s just colder. But at -40° or -50°C, Earth behaves in some ways like an alien planet. Plastic bags snap like potato chips. Pee crackles as it arcs through the air and freezes before it hits the ground. At the coldest temperatures, you can extinguish a match in a capful of gasoline. It’s almost as if physics itself changes at these temperatures.
Approximately -54°C. Photo: Jerry Kobalenko
Circulation
Any restriction of circulation, for example, has dramatic effects. Although mild frostnip on the cheeks and fingertips is hard to avoid, I’ve suffered actual frostbite only once. On that occasion, I was eating a sandwich while skiing. When it’s really cold, the only way to stay warm is to keep moving. So to eat lunch, I’d take a bite, then hold both the sandwich and the ski pole for a minute or two while shuffling forward and chewing, then take another bite.
It was very cold that day, and it turned out that holding the sandwich between thumb and forefinger for several minutes cut off circulation enough to frostbite my index finger. A big, painful blister formed, and the finger turned purple for a while. With care, it eventually got better, with no permanent damage. This happened on my first expedition, and it hinted how delicate the circulation can be at extreme temperatures.
A few years later, on another winter trip, one foot went numb for a few days. Although I didn’t look at it, I could tell it wasn’t frostbitten. Too much of a pins-and-needles sensation for that. Vaguely, I wondered whether it was the routine numbness that sets in on very cold expeditions: If the skin temperature stays below something like 10°C for several days, the nerves near the surface of the skin die, creating a numb sensation. When you get home, it takes two or three months for the nerves to regrow, after which feeling returns.
Still, it was strange that only one foot was affected. That had never happened before. Finally, one night in the tent I took off my camp bootie to inspect the foot. It looked fine, although the sock on that foot had slid down and bunched near the ankle. Perhaps this bunching had slightly hindered blood flow? I pulled up the sock, and a day later, feeling had returned to the foot.
Frost blisters: hard to avoid on the coldest expeditions. They hurt at first but eventually callous over, like a guitar player’s fingertips. Photo: Jerry Kobalenko
Based on such experiences, I now avoid wearing or doing anything that restricts circulation, even slightly, in the cold. Ski gloves often include an elastic band in the wrist that helps keep out powder snow if you’re barreling downhill. This is not a problem when you’re plodding along at three or four kilometres an hour, pulling a sled. If I otherwise like the glove, I cut it open and snip the elastic, to loosen the fit.
Stuffing a sleeping bag into a tight stuff sack in the morning can be painful, because materials become stiff in the cold and it hurts the hands to jam anything by force into a too-tight space. Essentially, stuff sacks are made for summer backpacking, where temperatures are mild and space is critical. Pulks have more space, so sleeping bags can be stuffed less painfully into an oversized bag. Other items — parka, tent — don’t need to be stuffed at all.
Many gloves have elastic around the wrist that keeps out snow and cold air but hinder circulation, so should be cut. Photo: Jerry Kobalenko
I no longer hold a sandwich while skiing, but I do minimize the length of rest stops. I follow the Seven Minute Rule: If I can get going again within seven minutes, the exercise metabolism — and accompanying warmth — has not had a chance to slow down. If it does, it takes almost half an hour to feel warm again.
Even wearing an extra layer during this warming-up period, the fingers usually go numb. When feeling returns, they hurt for several minutes. A physician I once traveled with explained that circulation may almost shut down, but lactic acid continues to build up in the tissues. When you warm up, and blood starts to flow again, the lactic acid is reabsorbed, and it hurts like hell. He called it reactive hyperemia. It is probably the same thing that ice climbers more colorfully dub the Screaming Barfies.
To avoid sweating, it’s important to wear the thinnest handwear (and clothing) possible. Here, numbness in the hands actually helps thermal regulation. When you’re already warmed up, if your hands start to go numb, you either need thicker gloves or another layer of clothing. (You can also pick up the pace slightly to generate more warmth.) I try the warmer handwear first. If the hands continue to go numb, I need another layer. Then eventually I switch back to the original, lighter glove.
Homemade fleece wristlets. Photo: Jerry Kobalenko
Most arctic gear is off-the-shelf, but there are a few custom items. I’ve worn wristlets in the cold for years, since reading that the 1986 Steger North Pole Expedition used them. At first, like Steger and his team, I used wristlets of knitted wool, but fleece models are easier to make and they last forever. They not only cover the vulnerable gap between glove and sleeve, but they add the equivalent of about half a layer of warmth, so you can wear slightly lighter gloves or mitts.
Mitts vs gloves
If you can get away with them, gloves let you do more. It’s hard to take pictures spontaneously, for example, if you have to remove mitts to click the shutter. But when it’s too cold or too windy, gloves are not enough. Everyone also has individual tolerances. My hands and feet have always been good in the cold, letting me sometimes get away with gloves, where some partners need mitts. Even expert travelers may require warmer handwear or footwear than others.
Socks
On cold expeditions, I wear two socks: a liner sock and a midweight sock. Between the two is a vapor barrier. I dislike vapor barriers, but I dislike it even more when boots freeze into blocks of ice, as sweat builds up over the weeks. You can buy vapor barrier socks, but I prefer big Ziploc bags. They’re just large enough for size 11 feet. Thinner, more comfortable bread bags rip, letting moisture into the boot, but a Ziploc endures for several days. As you eat through your food, you constantly have a new supply of empty Ziplocs.
In recent years, good liner socks have become extremely hard to find. Since the liners get wet inside the vapor barrier, they need to be synthetic. Light, tough nylon works best. Unfortunately, companies have discovered that making socks that cost $10 and survive 20 years of hard use is not a good business strategy. So socks, like so much other athletic and outdoor gear, have become expensive and high-tech, with different materials and weaves in different parts of the sock. They are often multi-hued and look tremendously stylish.
Because such socks are often made for competitive running or skiing, they fit tightly. In athletics, compression is said to lessen muscle fatigue, but in the Arctic, fatigue is better than frostbite. These socks leave tight bands around the lower legs. Even socks with less exaggerated marks make the feet colder at night.
In the cold, avoid tight athletic socks that leaves marks on the legs. Photo: Jerry Kobalenko
At normal workout temperatures, this tight fit may be beneficial, as advertised. At least, it doesn’t create problems. The blood flows freely, with room to spare. Not so at -40°. Any marks on the legs are a red flag that could presage numbness, cold feet or worse.
It is still possible to find synthetic liner socks that don’t constrict: They’re made for patients with diabetes, are widely available and perfect for arctic travel. There’s a delicious irony to wearing diabetic socks while chowing down all day on chocolate, brownies, candies, butter tarts, fudge and other scrumptious bonbons.
By the way, when we’re discussing -40° or so, we’re not counting windchill. Life may be harder in a wind — -50°C in still air is preferable to -30°C with a 35kph wind — but materials don’t get weird at -30°, wind or no wind. Circulation isn’t as hypersensitive.
Life below -40° is not easy. For certain chores, like taking down a tent, you need gloves part of the time. But at those temperatures, you can only use your fingers for a few seconds at a time: Squeezing anything is painful. So you work for a few seconds, then jam your hands back in mitts or in your pockets and let the pain subside and the feeling return. Then you work for a few more seconds. It takes ages to do anything, particularly in the morning when it’s coldest and before exercise has warmed you up.
Still, -40° is exciting, because it’s like little else on Earth, and it gives you a real sense of what it must be like to be an astronaut.
