Cold Page 11
It is November twelfth and eighteen degrees in Anchorage. My migratory timing has sent me back early, back to the cold, back to the coming of winter. Spring remains a long way off. The official start of winter is weeks away, but a thin veil of snow covers trees and houses and grass. The lakes around Anchorage have frozen, and where wind has blown the snow clear, ice crystals as big as flower buds blossom across their surfaces.
Here at Powerline Pass, above Anchorage, brown grasses poke out through thicker snow. Mixed with the grasses, fat stems of flower stalks, brown and dry, have split open just above the snow, their seams burst by expanding ice. Thigh-high shrubs — leafless, their bark scraped by moose teeth — stand with their heads and shoulders above the snow. Soon enough, the shrubs will disappear until spring, sleeping under the snow, away from the bitter cold and the wind that will careen down the surrounding slopes and through this mountain pass. The boughs of white spruce, sloped downward and out, already shed snow, and the snow piles up around them, while the ground immediately beneath them remains bare, protected by the umbrella of the boughs themselves and warmed by dark, sun-absorbing bark.
We are skiing, my son and I. For him it is the first ski of the season. He is awkward with his summer legs and new boots. He falls twice, but ten-year-olds bounce well, and his falls hinder neither pace nor exuberance. It is good, at times, to be in the cold. It stimulates the senses and the mind. Douglas Mawson, the Antarctic explorer, once wrote, “During the long hours of steady tramping across the trackless snow-fields, one’s thoughts flow…. The mind is unruffled and composed and the passion of a great venture springing suddenly before the imagination is sobered by the calmness of pure reason.” My son would express it differently. He would say it is fun. It might seem that his thin frame would chill easily, but he routinely sheds layers and complains when his teachers make him wear gloves at recess. Now he asks me to carry his hat and outer jacket, and then he rushes down the trail, skis flopping in rapid clumsy steps, poles gripped ham-fisted too far from his body, dark hair fluffed straight up by the discarded hat.
Stone Age pictures of skis and skiing appear on the walls of caves and on rocks. Four thousand years ago, the nomadic Sami, now incorrectly known as Laplanders, skied after the reindeer herds of Scandinavia. The word “ski” comes from the Norwegian skith, which means, literally, “wooden stick.” Until very recently, skis were wooden sticks. Specifically, they were birch sticks. Where my son and I ski now, we are too high for birch. There is only willow and spruce and alder. Our skis are made of a composite material. At this elevation, composite trees are at least as scarce as birch.
The physics of skiing is surprisingly complex. The pressure of a ski on snow combined with the movement of the ski creates friction, and friction generates heat. It is occasionally said, often with great authority, that the pressure of a ski lowers the melting temperature of the underlying snow and that movement of the ski adds heat through friction, creating a microscopic layer of liquid water that lets the ski slide. This explains why skis drag when temperatures drop. At minus thirty, when the snow is too cold to melt into microlayers of liquid water, the skier ceases gliding and begins to scrape. But it turns out that the idea of a microlayer of water between snow and ski may not be right. Something else may be going on. It may be that the molecules of frozen water at the surface of the snow, while still frozen, are not bound as tightly to the crystal lattice beneath. The surface molecules cannot grip other molecules above their heads and under their feet, so they slide around. It is their lack of grip that makes snow and ice slippery. This is a question of academic importance to certain physicists. But here is a fact: the Sami skiers did not care. They cared about reindeer. They learned by trial and error, not through the fundamentals of physics. My son cares no more than a Sami skier. He cares about fun and exuberance and feeling alive on a cool fall afternoon just beneath the treeline. He learns by falling and getting up and falling again.
Next to the trail we see a young moose, nascent antlers still intact, lounging in a snowbank, protected from the wind by a depression in the snow, chewing. Hot clouds puff out of his nostrils, and his jaws move in grinding circles, chewing cud. His expression, while dumb, is not quite so dumb as that of a cow. The peak of Denali — Mount McKinley — is visible far away to the north, beyond Cook Inlet. The mountain, from here, is entirely covered with snow. The weather on Denali at this time of year would be of Martian intensity, but at this distance it looks serene under its shroud of snow.
Someone has stapled a sign to a post next to the trail. The sign is fluorescent red, with the black silhouette of a grizzly bear. In thick letters, danger! appears beneath the bear’s image, which seems to smile slightly, as if up to something. At the bottom of the sign, in Magic Marker, someone has written, “Moose kill (by bear) near Williwaw Creek. Public use trail closed.” It is dated November fifth, a week earlier. We scan the hills hoping that the bear will stand out against the snow. All we see is the shadow of one mountain against another, with the bands of white spruce and shrubby willow creeping up the slopes, the treeline running higher in the gullies, zigzagging its way as far as it can before petering out, and above that just snow, and still higher on the steepest slopes exposed rock, wind-blown or just too steep to hold snow. It is in some ways like a coral reef, with certain species occurring on the reef flats and others in the gullies protected from waves, and the whole thing petering out in sand. After the Philippines, the wind, though hardly cold by any reasonable standard, bites my cheeks. We ski onward, toward the pass.
Plants, without exception, do not migrate. Some die off each autumn, leaving behind seeds that germinate the following spring, analogous to the overwintering eggs of insects. Some die off aboveground but have roots that survive underground. Certain grasses and herbs and shrubs overwinter with their branches and leaves buried under snow, dormant and hidden, hibernating. Trees, though, stand out in the open, dormant but exposed, not dug into a burrow or cave or snow mound like some cowering, thin-blooded hibernator. The dahurian larch is the world’s northernmost tree of any real size. It looks something like a spruce, but its needles turn orange and fall off each autumn. It can be three feet thick at the base of its trunk. It survives the winter cold of the far north, standing in the open at temperatures of ninety below zero, not counting windchill. Its forests look like stands of Christmas trees, sometimes densely packed but sometimes scattered, in Mongolia, North Korea, northern China, and Siberia. It grows as far north as the Khatanga River valley on Russia’s Taymyr Peninsula, the northern extent of mainland Asia. The latitude there is seventy-two degrees, two degrees farther north than the treeless tundra of Alaska’s North Slope, where the dahurian larch is absent not because it cannot survive, but because the vagaries of geobotanical history and the total absence of landscape gardeners have never brought it there. Make no mistake: this is one tough tree. The dahurian larch is the plant kingdom’s answer to Apsley Cherry-Garrard and Father Henry and Ernest Shackleton. It knows how to handle cold weather.
Other trees, softer than the dahurian larch, drop out one by one as the weather becomes colder. First the palm and the mosquito-infested mangrove, killed by nothing more than a hard freeze, and then the shade-tree live oak with its thick branches spread out like umbrellas, dead at eighteen degrees. The redwood and the southern magnolia and the slash pine give up at five degrees above. The sweet gum is gone at seventeen below. Then the maple and the shagbark hickory and the hop hornbeam give way to the frost. And finally it is too much even for the spruce and the dahurian larch, and the forests are gone. Almost gone, because there are still the bonsai trees, the diminutive trees that hardly seem like trees at all, except that they have woody stems and leaves and they are in fact species of birch and willow. There is Betula nana, a birch that grows no more than a few feet tall and looks nothing like its full-size cousin the white-barked Betula papyrifera, the paper birch, the tree of the birchbark canoe. And the willows: Salix arctica, Salix ovalifolia, Salix reticulata, a
nd others, none more than a few inches tall. Compare these to Salix nigra, the black willow, the tree of the shifting sand islands and banks of the Mississippi River, its trunk obese, its branches reaching higher than a ten-story building, its leaves longer than the full height of its Arctic cousins, its ability to survive a real winter virtually nonexistent.
Some of the tiny cold-climate willows spread like vines across the ground, but others grow like stunted stately trees, with thick trunks and smaller branches and dense accumulations of tiny leaves, all reduced, all low to the ground, forming forests odd not only for their tiny size but also because the grass, in summer, towers above the trees. An ecologist looking at these miniatures might describe an understory of trees and a canopy of grass. Reduced size lets these willows hide under snow, avoiding the worst of the cold and the moisture-starved winter winds that would suck the water from frozen sap. Without snow cover, the tiny trees would be forced to replace lost moisture, to somehow pull water from frozen ground. More likely, the trees would die.
Many trees — perhaps most — can survive at temperatures far below those found where the trees grow. Cold of twenty below will not kill the bald cypress, but the bald cypress is not found in climates this cold. The same is true for the Oregon white oak and the red pine and eastern hemlock. Even the paper birch, the quaking aspen, and the black spruce, trees of the far north, would survive in temperatures colder than those where they are found. But it is not only the cold and dry air they have to face. It is the wind, and even the weight of snow. The wind, kicking up ground blizzards and carrying sharp-edged ice crystals, can sand-blast a tree, stripping off bark on the upwind side and exposing raw tissue, killing and polishing the cambium, the tissue beneath the bark that shuttles nutrients between leaves and roots. Blowing snow can kill the upwind branches, leaving a tree that looks like a flag, its living branches all pointing downwind. It can prevent trees from growing upward, leaving them prostrate on the ground. Or, for trees that struggle through the first ten or twenty or thirty feet of height, it can leave a tree mop-headed, able to form thick concentrations of needles on branches high above the blowing snow and ice of ground blizzards.
Accumulated snow, piled on in the absence of wind, can snap a tree in half. Trees forty feet tall sometimes hold more than six thousand pounds of snow. Certain trees have evolved to shed snow. The branches of spruce trees arc gracefully downward, allowing snow to slide to the ground. Fir boughs flex, dumping snow without breaking. When an ice storm hits a forest of oak or maple or ash before leaves have been shed, the weight of ice on leaves fractures branches, limbs, and even trunks, or pulls whole trees over, ripping their roots from the ground, sending them tumbling into houses, laying them across roads, or suspending them in mid-descent on power lines, wreaking havoc. In Finland, on certain mountain slopes, breakage from snow loading controls the extent of forestation. The treeline is controlled by the weight of snow.
A tree that tolerates sand-blasting and survives snow loading still has to withstand freezing. A tree cools gradually, following the air temperature downward. But like the blood of certain insects, the tree’s fluid supercools, dropping below the freezing point without actually freezing. At some point, supercooling fails, and the liquid between the tree’s cells freezes, not gradually but suddenly. It flash freezes. Molecules, one moment drifting about with the freedom of a liquid state, lock into place, still. In doing so, they dump energy. The act of freezing, of changing from a liquid state to a solid state, releases heat. This is not an abstract concept. Insert a thermometer in a tree, wait while the tree freezes, and record a temperature spike as liquid turns to solid. A beech tree cools steadily to seventeen degrees, the spaces between its cells flash freeze, and its temperature spikes back up to thirty. And then it cools some more, going back into a steady, slow decline.
Outside the cells, in the spaces between them, the tree is frozen. But inside the cells, the fluid is full of dissolved solids, salts, and sugars. The complex molecules of the factory of life float about in each cell’s cytoplasm, suspended by water molecules, and the water molecules in the cell are moving around, bouncing off one another, dancing like ten-year-old boys souped up on marshmallows. Some dance right through the cell membrane and, once outside, freeze. This is a form of cryosuction, the same cryosuction that sucks liquid water toward layers of segregation ice in soil. It is cryosuction pulling water molecules across the cell’s membrane, drawing them out of the cell. At the same time, the cell membrane opens up, yielding to cryosuction. In cold-hardened trees, cell membranes become increasingly permeable, letting the water go before it can freeze inside the cell and create deadly sharp ice crystals within it. This is part of the reason trees can handle much colder temperatures at the beginning of winter than at the beginning of autumn. As a consequence of cold hardening, the fluid inside cells — the cytoplasm — becomes less wet. The dissolved salts, sugars, and proteins become more concentrated. As with all liquids, the greater the concentration of dissolved solids, the lower the freezing point. This protection is not without limits. At some point, the cells freeze, and ice crystals inside the cells spell death. Or the cells do not freeze, and the concentration of dissolved solids inside the cells increases beyond tolerance, spelling death. Either way, cells die. Kill enough of them, and the tree itself goes the way of Robert Falcon Scott or Lieutenant George De Long or the three frozen sons of Johann Kaufmann in the School Children’s Blizzard of 1888.
It is November twenty-eighth and minus fifteen degrees at the Chena Hot Springs Resort, sixty miles west of Fairbanks. For ten dollars, I walk on a concrete floor, through a locker room, into a heated indoor pool room, and then outside — in a bathing suit and bare feet. Hitting the minus-fifteen-degree air is like walking into a brick wall. I can feel the cold inside my nose, a feeling of dry boogers that I know are not boogers at all, but ice.
The rock pool, steaming with geothermal heat, is fifteen cold paces away. Steam rising from the pool freezes to the first thing it finds. The rails around the rock pool are covered with ice. Beyond the rails, the pool is surrounded by boulders, also covered with ice. Behind the boulders are trees, what seem to be small spruce trees, covered, too, with ice. The ice covering the rails, the boulders, and the trees is white, not clear.
I wade into waist-deep water and immediately submerge, soaking up the heat. The rock pool is four feet deep and well over a hundred degrees, the temperature of a hot bath. The smell of sulfur rises with the steam. I wade toward the far end of the pool, where the hot spring spills into the pool, and the water is noticeably warmer. The cold air, over a distance of maybe thirty feet, is sucking the heat right out of this water. Gravel covers the bottom of the pool. Green and red lights illuminate the steam coming off the water. The sky beyond the steam is crystal clear, frozen into transparency. Low on the horizon, through the steam, snow-covered hills reflect starlight. Overhead, the stars themselves burn — the Big Dipper and, almost directly above, the North Star. I reach up to run my hand across my scalp. My hair is frozen. I submerge, and the ice, for a moment, disappears.
A man speaks from the edge of the pool. “I’m celebrating my son’s house,” he tells me. This seems to me an odd statement, out of the blue, to emerge from the steamy shadows at the edge of the pool. I move closer, expecting to see someone with him, but he is talking to me. “We’ve been working on it for three years,” he says, “and today was the final inspection. We’re done, and we’re celebrating. It has double-insulated walls.” The man has lived in Fairbanks his entire life. He is Bergmann’s Rule personified, at least three hundred pounds, insulated from the cold of Fairbanks by thick flesh that gives him a rounded appearance, something like that of a northern seal. He tells me that he is in his sixties. He seems eager to explain that he is retired, maybe as an explanation for his need to converse, to feed a hunger for conversation that was once filled by coworkers. But it is not so much conversation as monologue. It is not clear to me that my presence actually matters. Increasingly, I feel
like one of the monkeys at Jigokudani Park in Japan, which like to bathe in hot springs through the Japanese winter, jabbering in meaningless primate patter, surrounded by steam and frost, falling into a stupor induced by heat and sulfurous fumes.
“We had snow in June this year,” the man says. “Snow and a hard frost. It killed all of the flowers in the yard. Of course, we had more flowers. The garage was full of flowerpots. Only the ones in the yard were killed. It slowed down the construction season, too. We got a late start on my son’s house. But it’s done now.”
I dunk to thaw my hair. Is it rude to dunk in mid-monologue, the only listener suddenly disappearing underwater? But when I surface, he is still talking. “There’s not enough snow to ski,” he is saying. “Last year we had better snow. When I ski, I ask for the slowest skis they have. I’m scared of skiing. I’m afraid of skiing too fast.” He is too obese for skis. It is hard to imagine him on skis. My hair is frozen again, so I submerge and inch backward. When I resurface, he is hidden by steam, but his voice goes on as if I have not moved. I continue to back away until his voice is muffled in steamy darkness.
Later, leaving the rock pool, I find my towel stiff as a board, coated with frozen steam. Before I get inside, the hairs on my arms and chest freeze. They become brittle. When I move my arms, I can feel the hairs breaking under the strain. I am pleasantly overheated from the pool. I feel slightly dizzy, the stupor of a Jigokudani Park monkey. Eight inches of ice hang from the handle of the door going into the heated pool room. Just outside the locker room, a map with pushpins shows the homelands of visitors. There are three pins in Japan, one in Afghanistan, many in China, one in Belarus, a few in Russia. The Lower 48 states are well pinned.
Dressed, I walk for a few minutes in the compound. My hair, still damp, freezes again. My ears grow cold, but I am otherwise warm, parboiled, wearing only a sweater and a light jacket. On one side of the compound, the owners have erected an entire building made from ice. They call it the Aurora Ice Museum, but it looks more like a church. Inside, there are ice sculptures. There is an ice bar, with fifteen-dollar martinis served in glasses made from ice. It is possible to rent the church of ice for corporate events, for birthday parties, for weddings. Wedding ceremonies are held at an ice altar. For just under two thousand dollars, guests can participate in a three-day ice-sculpting class.