Cold Read online

  Elsewhere, for around six hundred dollars, it is possible to stay in an ice hotel. Ice hotels are a new phenomenon, the first one appearing in 1989. Most winters, tourists have choices. There are at least six solid-ice hotels in the world, in places such as Norway, Sweden, Finland, Romania, and Quebec.

  By the time I get to my traditionally built hotel room, I have cooled off. The night has dropped another three degrees, to minus eighteen. In my room, a sign taped to the air conditioner says, “Please do not use air conditioning September 15th to May 15th.”

  Charles Darwin, seasick, sailed into Tierra del Fuego, near the southern tip of South America, in 1832. It was December, the middle of summer in the Southern Hemisphere. “The climate is certainly wretched,” Darwin wrote. “The summer solstice was now passed, yet every day snow fell on the hills, and in the valleys there was rain, accompanied by sleet. The thermometer generally stood about 45 degs., but in the night fell to 38 or 40 degs.”

  He described the forests, noting in particular the treeline: “The mountain sides, except on the exposed western coast, are covered from the water’s edge upwards by one great forest. The trees reach to an elevation of between 1000 and 1500 feet, and are succeeded by a band of peat, with minute alpine plants; and this again is succeeded by the line of perpetual snow.”

  The trees survive as best they can, but it was not so much the trees that interested him as the people.

  While going one day on shore near Wollaston Island, we pulled alongside a canoe with six Fuegians. These were the most abject and miserable creatures I anywhere beheld. On the east coast the natives, as we have seen, have guanaco cloaks, and on the west they possess seal-skins. Amongst these central tribes the men generally have an otter-skin, or some small scrap about as large as a pocket-handkerchief, which is barely sufficient to cover their backs as low down as their loins. It is laced across the breast by strings, and according as the wind blows, it is shifted from side to side. But these Fuegians in the canoe were quite naked, and even one full-grown woman was absolutely so. It was raining heavily, and the fresh water, together with the spray, trickled down her body. In another harbour not far distant, a woman, who was suckling a recently-born child, came one day alongside the vessel, and remained there out of mere curiosity, whilst the sleet fell and thawed on her naked bosom, and on the skin of her naked baby!

  Since Darwin’s time, the Fuegians — the Yamana, Selk’nam, Manek’enk, and Alacalufe — have been admired for their ability to withstand the cold. Take a man of European, African, or Asian heritage, lay him down next to an Alacalufe native of Tierra del Fuego, and it is not the native who is abject and miserable, but the shivering European or African or Asian. The European or African or Asian shivers to maintain a reasonable body temperature, while the Alacalufe stays warm without shivering, through what is sometimes called “nonshivering thermogenesis.” They have physiologically adapted to cold, with a metabolic rate as much as forty percent higher than that of other races allowing them to maintain a normal body temperature while sleet runs off their skin.

  In Darwin’s day, the Aborigines of Australia slept naked on the ground, even in the colder southern regions of the continent, where temperatures might drop below freezing. Unlike the Alacalufe, the Aborigines did not stay warm. They had adapted to cold through a different path than that taken by the Alacalufe. An Aborigine lying on the ground would become colder than a European, an African, or an Asian. His body temperature would drop. When it hit the point that would trigger shivering in the European or African or Asian, the Aborigine would not shiver. His body temperature would keep dropping. He would enter a state of shallow hypothermia, unperturbed. During the night, his core temperature might drop four degrees, to ninety-five degrees. He would then enter what has been called a state of “nightly torpor,” perhaps something like that of hungry tit-mice or finches, which in turn is something like daily hibernation, which in turn has been compared to suspended animation. Today Australian Aborigines sleep in heated homes, but presumably they could still enter into nightly torpor, maybe dreaming through shallow hypothermia, while other Australians would shiver, likely not sleeping at all, and would appear, and in fact be, abject and miserable.

  There may be differences, too, among Europeans and Africans and Asians. During the Korean War, it became evident that frostbite was more prevalent among black soldiers than among white soldiers. On average, black men were four times more likely than white men to suffer injuries from the cold, and black women were twice as likely to suffer injuries as white women. “Arabs,” wrote a doctor reporting these data, “appear to be similarly predisposed, as are individuals from warmer climates.” But individual variability would be considerable, with some black men and Arabs facing the cold with far more aplomb than most of their white colleagues.

  Blood circulation to the skin and hands is greater in Inuit people — Eskimos — than in Europeans, apparently protecting them from frostbite. Norwegian fishermen have shown similar tendencies. Korean and Japanese ama divers — traditionally women who dive on a breath of air after seaweed, shellfish, and pearls — have a legendary tolerance for cold water. A century ago, they often dove topless, spending hours each day in the water. Today they wear wet-suit tops or tights. Whatever physiological tolerance they once had has diminished but not disappeared.

  A certain amount of adaptation is possible. In 1960, a University of Alaska physiologist named Laurence Irving noticed two students wandering around the Fairbanks campus in light clothes and without shoes. The students were adhering to the rites of a religious sect that discouraged the wearing of shoes, a practice that must have originated somewhere warmer than central Alaska. Irving put the students in a room chilled to thirty-two degrees, then measured the temperature of their fingers and toes for an hour. Their toes and fingers would cool off, then warm up again, apparently as blood vessels constricted but then dilated, sending warm blood to the extremities before they became dangerously cold. The students did not shiver until after fifty minutes. Irving did the same with an air force volunteer but had to discontinue the experiment after thirty minutes. “The airman’s toes,” he wrote, “became so painful and he began to shiver so violently that I caused him to terminate the test lest he shake himself apart.”

  Quebec City postal workers, walking from mailbox to mailbox through the Canadian winter, grow more cold tolerant as winter wears on. Heart rate and blood pressure drop. Workers in Antarctica are said to adapt over time by increasing their core temperature. Charles Wright, who traveled with Scott in Antarctica but was not chosen for the fatal trek to the pole, trained himself for the cold even as a child. “For some incredible reason,” he told an interviewer, “I thought it was a good thing — I was living in Toronto at the time — to toughen oneself a bit, so I wore the same clothes in summer and winter.”

  Habituation to cold might disappear after a few winters in Florida but be regained with a return to colder regions. By contrast, the genetically programmed tolerance of the Alacalufe, the Australian Aborigine, and the Inuit would be more long lasting. But all of this habituation in human postal workers and Arctic explorers, all of the genetically conferred advantages of the Alacalufe and the Australian Aborigine and the Inuit, offer no more than the smallest advantages. Compared to the arctic fox or the wolf or the musk ox, compared to the ground squirrel or the wood frog or the poorwill, the most cold-hardened human, if forced to rely on physiology alone, is as fragile as thin ice. A human without thick clothes or shelter or fuel will freeze to death in conditions too warm to trigger shivering in a moose. At the end of summer, the human response is primarily one of putting on clothes, lighting a fire, and turning up the thermostat. Or, alternatively, of frostbite and death by hypothermia.

  DECEMBER

  It is December third and twenty-six degrees in Anchorage. Heat leaks through roofs, and melting snow drips over gutters, turning into thick icicles that threaten to crash down, dangerous, not sharp enough to impale but heavy enough to bludgeon. The sk
y is over-cast, the clouds forming a vaporous blanket that holds in the heat. Thanksgiving week, with six straight days below zero, has defrosted. The clear, cold nights of November, loitering in the teens, have migrated.

  The entire state suffers in the heat. Juneau, the capital, hit thirty-nine. Anchorage is warmer than Chicago, Des Moines, Minneapolis, Salt Lake City, and Grand Rapids, and almost as warm as Omaha, Seattle, and Albuquerque. The North Slope hit twelve degrees. Fairbanks, in the icy interior, is in the positive digits, four above.

  This is inconvenient but not terribly unusual. In 1929, Anchorage hit fifty-one degrees on December third. People in Anchorage grow accustomed to winter heat waves driven by what fur traders called the chinook winds — winds that came from the land of the Chinook tribe, in the Pacific Northwest. The Alaskan version of the chinook winds blow into Anchorage with some regularity, their hot breath melting the snow, leaving streets filled with water and turning forest floors into slushy swamps. It happens so abruptly that the chinook winds are sometimes said to eat the snow. On the mountainsides above Anchorage, chinook winds can reach hurricane strength. The loss of roofs from hillside houses is not unknown, giving wealthy homeowners exceptional but unexpected views of crisp winter skies. Anchorage is not unique in suffering from these winds. In 1972, a chinook wind blew into Loma, Montana, raising temperatures from 54 below to 49 above, a change of 103 degrees in twenty-four hours.

  But today’s heat wave did not blow in on a chinook wind. It was forecast by the National Weather Service in October. Using data from satellites and ocean buoys moored in water more than three miles deep, the National Weather Service warned that we would have an El Niño year. A week ago, the Climate Prediction Center in Maryland issued an advisory: “El Niño conditions should intensify during the next one to three months.” For Alaska, this December through February will be warmer than normal.

  Long before it came to the attention of meteorologists, El Niño was noticed by South American fishermen, who recognized warm currents off Peru and Ecuador each year around Christmas. The warm currents killed the fishing. The fishermen named the annual event El Niño, “the Little One,” in honor of the birth of Christ. Globally, El Niño has come to refer to those years when the Christmas currents are unusually strong. The currents strengthen when trade winds blowing to the west weaken and unusual volumes of warm water reach Peru and Ecuador. Global weather patterns respond. It rains in California. Australia dries out, and bush fires burn out of control. Gulf of Mexico hurricanes become less prevalent. South China Sea typhoons become more prevalent. Corals die in the Pacific Ocean. People catch marlin off the coast of Washington State. With El Niño, cold, clear high-pressure air stalls between Alaska and Seattle. The pressure ridge forces warm winds forming along the Aleutian Islands to swing north, toward Anchorage. The city will have rain within days.

  This is no chinook wind, but our snow will be eaten all the same.

  The moose is so well insulated that the southern border of its range is sometimes said to be set by its intolerance of heat. A moose has two kinds of fur — thick guard hairs that give it color and finer underfur that keeps it warm. Piloerection is the fluffing out of hair, often for the purpose of staying warm — for increasing the insulative effectiveness of hair. In humans, piloerection, rendered useless by millions of years of evolution, causes goose bumps. In moose, the fur is so efficient that piloerection does not occur until the mercury drops below minus ten. A moose’s metabolism does not increase until minus twenty. But even on a mild winter night without wind, the moose will lose the energy equivalent of a Snickers bar every hour. It needs to eat or lose weight. In fact, it does both.

  A moose in Alaska’s Denali National Park might feed six hours each day, swallowing more than thirty pounds of branches and bark. Then it ruminates for another twelve hours. In this context, ruminating is not a matter of turning something over in the mind, as a human might do, but rather of chewing cud. Like a cow, the moose regurgitates partly digested food from its first stomach, chews it, and reswallows. The jaw muscles, ruminating, generate heat. The four stomachs, churning, generate heat. Microbial action in the gut generates heat. A ruminating moose might generate fifty percent more heat than a fasting moose. But in winter, the food is tough to digest. Branches and bark are less nutritious than the fresh green shoots and leaves and flowers of spring and summer. The amount of food that the moose can process is limited by the number of hours in a day. It is possible for the moose to starve to death with its stomachs full, unable to keep up with energy demands.

  The moose has to decide how hard it will search for food. Though seemingly dim-witted, it knows at some level that it is not likely to find high-quality forage in the snow. It knows, too, that movement through snow is no easy task. It lifts its long legs high to step over the snow and even plows through deep snow, looking for thinner patches, following the tracks of other moose or wind-scoured frozen rivers or ski trails. But when the snow is deep, the moose must reduce its range. It may wander over no more than ten or twenty acres, conserving energy, chewing its cud, burning its fat, stripping bark from trees. It will sit in the snow in preference to standing, using the snow as a blanket. Foraging, successful or not, will use at least twenty percent more energy than sitting in the snow. On sunny days, the moose will move into the open. On cold nights, it will sleep under thick spruce cover. It will burn ten thousand calories or more in a day, twice that of a well-fed Arctic explorer. Like the Arctic explorer, the moose will lose weight.

  The moose has been called a “confronter” or a “tolerator” or, more descriptively, a “winter active,” because it confronts winter. It tolerates winter. Winter actives neither hibernate nor migrate. The formula they pursue seems simple: take in as many calories as you can, preserve your fat, and hope for the best.

  Winter actives have fur that holds in heat. The arctic fox, curled up in a ball, wrapped in its own fur, lies comfortably on the northern pack ice at forty below, steadfastly refusing to shiver. The winter coat of the caribou is so warm that the animal uses less energy in winter than in summer. Musk oxen in small herds of ten or fifteen, when harassed, circle up, horns out and heads down, their hair hanging matted, windblown and iced, their expressions Pleistocene. They refuse to run not because they are stupid, but because their coats are so warm that to run is to overheat. Other animals have layers of fat that not only buffer winter food shortages but also provide insulation. They wear sweaters of fat. An inch of fat provides more insulation than an inch of wool. A male polar bear ambles across the pack ice throughout winter, feeding on seals. It enters the cold season rotund, wearing the equivalent of eight or ten wool sweaters under its fur.

  Where fur and fat are not enough, there is shelter. Gray squirrels, unlike ground squirrels, do not hibernate. Instead, they make nests of twigs, maybe ten inches in diameter. Inside, a well-made gray squirrel’s nest might have twenty layers of leaves, and inside the leaves might be finely shredded bark, and inside the finely shredded bark might be a four-inch-wide chamber, a gray squirrel’s winter parlor, its home between bouts of foraging. Flying squirrels make similar nests. The insulation of a flying squirrel nest can weigh five times more than the squirrel itself. Naturalist Bernd Heinrich once chased a flying squirrel from its nest, put a hot potato in the insulated chamber, and watched it cool. At nine degrees outside, the potato cooled less than thirty degrees in half an hour. Put another way, the potato was still hot enough to eat after thirty minutes in a flying squirrel’s nest with the outside temperature at nine degrees above zero.

  Winter actives have other tricks and adaptations. Beavers and muskrats huddle with their families, sharing their warmth. The feet of snowshoe hares are so enlarged relative to their weight that they walk on the snow’s surface without breaking through. Their foot loads, as they are called, are comparable to those of a human wearing snowshoes that are ten times the size of a human foot. Caribou plant their front feet at a steep angle, supporting their weight in the snow on the hoof
, the upper part of each foot, and the dewclaw — a toelike protuberance sticking out from the back of what looks like the animal’s ankle. Likewise, lynx, wolves, and wolverines float across the snow’s surface on enlarged feet.

  Some winter actives store food. The gray squirrel stores nuts. The fox caches eggs and frozen carcasses and biscuits stolen from Dumpsters. The diminutive half-rabbit, half-hamster, half-pint pika — known variously as the rock rabbit, the whistling hare, and the coney — dries herbs in the summer sun, making herb hay while the sun shines, then stores it in the caves and crevices of rock falls. By winter, an individual pika, weighing a third of a pound, may have half a dozen two-pound piles of herb hay scattered in the rocks.

  The snow itself is shelter. The subnivean dwellers — the lemmings and voles and shrews — are winter actives. Their tunnels in the snow hover right around freezing through the winter. It is not just a matter of insulation. If it grows colder above their snow tunnels, liquid water in the snowpack freezes, and in so doing releases heat, keeping the temperature in the subnivean caverns warmer than it might otherwise be. If it grows warmer above the snow, the snow goes from a solid to a liquid, and in so doing absorbs the heat. The end result is stability, in some ways as important as warmth. For the subniveans, it is safer under the snow, and through most of the winter, it remains warmer beneath the snow than above, and there is no wind. If winter behaves well, if the chinook winds are not too severe, if unexpected warming does not ruin the winter season, the subnivean winter actives know what to expect. But if it grows too warm for too long, tunnels can flood, forcing the subniveans to the surface, where they face not only the elements but also hungry predators.