The Natural Landscape in Alaska

Glaciers

In 1986, Hubbard Glacier, north of Yakutat, suddenly decided to surge forward, cutting off Russell Fjord from the rest of the Pacific Ocean. A group of warmhearted but ill-advised wildlife lovers set out to save the marine mammals that had been trapped behind the glacier. Catching a dolphin from an inflatable boat isn't that easy -- they didn't accomplish much, but they provided a lot of entertainment for the locals. Then the water burst through the dam of ice, and the lake became a fjord again, releasing the animals anyway. In 2002, it happened again (no rescue this time). Ships were warned away as the 70-square-mile lake, having risen 61 feet above sea level, quickly drained through a 300-foot-wide channel with a whoosh. Geologists say it could happen again anytime.

Bering Glacier, the largest in North America (about 30*145 miles in area), can't decide which way to go. Surging and retreating on a 20-year cycle, it reversed course in 1995 after bulldozing a wetland migratory bird stopover, and speedily contracted back up toward the mountains. Yanert Glacier surged 100 yards a day in 2000 after moving 100 yards a year since 1942. The next year, Tokositna Glacier started galloping after 50 years of quiet. In 1937, surging Black Rapids Glacier almost ate the Richardson Highway. In Prince William Sound, Meares Glacier plowed through old-growth forest. On a larger scale, all the land of Glacier Bay -- mountains, forests, sea floor -- is rising 1 1/2 inches a year as it rebounds from the weight of melted glaciers that 100 years ago were a mile thick and 65 miles long.

These new and erased lands are just small corrections around the margins compared to all the Earth has done in setting down, wiping out, and rewriting the natural history of Alaska. In the last Ice Age, 15,000 years ago, much of what is Alaska today was a huge glacier. Looking up at the granite mountains of Southeast Alaska, especially in the Lynn Canal, you can see a high-water mark near their towering peaks -- the highest point to which the glaciers reached.

The living glaciers of Alaska, like living fossils from the last Ice Age, helped figure out how glaciers work. In the 1830s, scientists in Switzerland found huge rocks (now called glacial erratics) that appeared to have moved miles from where they had once been a part of similar bedrock. Scientists theorized that ancient glaciers shaping the Alps must have moved the rocks. John Muir, the famous writer and naturalist, maintained in the 1870s that the granite mountains of Yosemite National Park had been rounded and polished by the passing of glaciers that melted long ago (he was only partly right). He traveled to Alaska to prove it. Here, glaciers were still carving the land -- they never finished melting at the end of the last glacial period -- and Muir could see shapes, like those at Yosemite, being created. Glacier Bay, which Muir "discovered" when guided there by his Alaska Native friends, was a glacial work in progress, as it still is today.

When you visit, you'll see moraines, heavy blue ice and white snow streaked with black rock and dust, obviously gouged from mountains and left at the faces and along the flanks of the glaciers in debris piles. Today Alaska's 100,000 glaciers cover about 5% of its landmass, mostly on the southern coast. There are no glaciers in the Arctic -- the climate is too dry to produce enough snow. The northernmost large glaciers are in the Alaska Range, such as those carving great chasms in the side of Mount McKinley. At that height, the mountain creates its own weather, wringing moisture out of the atmosphere and feeding its glaciers. The Kahiltna Glacier flows 45 miles from the mountain, descending 15,000 feet over its course. The Ruth Glacier has dug a canyon twice as deep as the Grand Canyon, half filled with mile-deep ice. Similarly, fjords and valleys all over Alaska were formed by glaciers that covered North America over the last 2.5 million years.

Earthquakes & Mountains

Alaska has an average of 13 earthquakes a day, or 11% of all the earthquakes in the world, including 3 of the 10 largest ever recorded. On November 3, 2002, Alaska felt the world's largest earthquake of the year and one of the largest ever in the United States. Waves slopped across the bayous of Louisiana, and geysers at Yellowstone changed their size and period of eruptions. No one died and few people were injured because the quake occurred in such a sparsely populated area, the region between Anchorage and Fairbanks in the Alaska Range east of Mount McKinley. A 140-mile-long crack appeared right across that region, running over mountains and through glaciers. The land on each side moved laterally as much as 22 feet and vertically up to 6 feet.

It's all part of living in a place that isn't quite done yet. Any part of Alaska could have an earthquake, but the Pacific Rim from Southcentral Alaska to the Aleutians is the shakiest. This is where Alaska is still "under construction." The very rocks that make up the state are something of an ad hoc conglomeration, still in the process of being assembled. The floor of the Pacific Ocean is moving north, and as it moves, it carries islands and mountains with it. When they hit the Alaska plate, these pieces of land, called terranes, dock like ships, but slowly -- an island moving an inch a year takes a long time to travel thousands of miles. Geologists studying rocks near Mount McKinley found a terrane that used to be tropical islands. In Kenai Fjords National Park, fossils have turned up that are otherwise found only in Afghanistan and China. The slowly moving crust of the earth brought them here on a terrane that makes up a large part of the south coast of Alaska.

Living in such an unsettled land is a matter of more than abstract interest. The Mount Spurr volcano, which erupted most recently in 1992, turned day to night in Anchorage, dropping a blanket of ash all over the region. A Boeing 747 full of passengers flew into the plume and lost power in all its engines, falling in darkness for several minutes before pilots were able to restart the clogged jets. After that incident, the airport was closed until aviation authorities could find a way to keep volcanic plumes and planes apart. In early 2009, the Anchorage airport repeatedly closed due to eruptions of Redoubt Volcano, stranding thousands of passengers for days. Such events underline the remoteness of Alaska -- you can't just take a bus. With more than 80 active volcanoes, it could happen again at any time; your only defense is travel insurance. Find up-to-date volcano monitoring information at the Alaska Volcano Observatory website (www.avo.alaska.edu).

Earthquakes between 7 and 8 on the Richter scale -- larger than the 1994 Los Angeles quake -- occur once a year on average, and huge quakes over 8 averaged every 13 years over the last century. The worst of the quakes, on March 27, 1964, was the strongest ever to hit North America. It ranked 9.2 on the Richter scale, twisting an entire region of the state so land to the west sank 12 feet, while on the east it rose more than 30 feet. More land moved laterally than in any other recorded earthquake. The earthquake destroyed much of Anchorage and several smaller towns, and killed about 131 people, mostly in sea waves created by underwater landslides. In Valdez, the waterfront was swept clean of people.

But even that huge earthquake wasn't an unusual occurrence, at least in the Earth's terms. Geologists believe the same Alaska coast sank 6 feet in an earthquake in the year 1090.

Permafrost & Sea Ice

The northern Interior and Arctic parts of the state are less susceptible to earthquakes, and since they receive little precipitation, they don't have glaciers, either. But there's still a sense of living on a land that's not permanent, since most of northern Alaska is solid only by virtue of being frozen. When it thaws, it turns to mush. The phenomenon is caused by permafrost, a layer of earth just below the surface that never thaws -- or, at least, you'd better hope it doesn't. Buildings erected on permafrost without some mechanism for dispersing their own heat -- pilings, a gravel pad, or even refrigerator coils -- can thaw the ground below and sink into a self-made quicksand. With the climate warming, sections of the Trans-Alaska pipeline are leaning, and many miles of highway in Interior Alaska are being rebuilt each year because the ground they traverse has turned to mush.

The Arctic and much of the Interior is a swampy desert. Annual precipitation measured in Barrow is the same as in Las Vegas. Most of the time, the tundra is frozen in white; snow blows around, but not much falls. It melts in the summer, but the water can't sink into the ground, which remains frozen. Water on top of the permafrost layer creates huge, shallow ponds. Alaska is a land of 10 million lakes, with 3 million larger than 20 acres. Birds arrive to feed and paddle around those circles and polygons of deep green and sky blue.

The permafrost also preserves many things. Although few and far between, tractor tracks remain clearly delineated for decades after they're made, appearing as narrow, parallel ponds reaching from one horizon to the other. The meat of prehistoric mastodons, still intact, has been unearthed from the frozen ground. On the Arctic Coast, the sea eroded ground near Barrow that contained ancient ancestors of the Eskimos who still inhabit the same neighborhood. In 1982, a family was found that apparently had been crushed by sea ice up to 500 years ago. Two of the bodies were well preserved, sitting in the home they had occupied and wearing the clothes they had worn the day of the disaster, perhaps around the time Columbus was sailing to America.

Sea ice is the frozen ocean that extends from northern Alaska to the other side of the world. For a few months of summer, it pulls away from the shore. Then in October, icebergs floating toward land are cemented together by new ice forming along the beach. But even when the ice covers the whole ocean, it still moves under the immense pressure of wind and current. The clash creates towering pressure ridges -- piles of broken ice that look like small mountain ranges and are about as difficult to cross.

The National Weather Service keeps track of the ice pack and issues maps and predictions online (www.arh.noaa.gov). Eskimo hunters traveling on the ice by snowmobile need this information, as do crabbers who tempt disaster by fishing the south-moving ice edge in the fall and shippers looking for the right moment in the summer to venture north with barges of fuel and other supplies for the coast of the Arctic Ocean. Sometimes there is barely time in the summer to get there and back before the ice closes in again in the fall.

Rainforest

By comparison, southern coastal Alaska is warm and biologically rich. Temperate rainforest ranges up the coast from Southeast Alaska north into Prince William Sound and westward to Kodiak Island, with bears, deer, moose, wolves, and even big cats living among the massive western hemlock, Sitka spruce, and cedar. This old-growth forest, too wet to burn in forest fires, is the last vestige of the virgin, primeval woods that seemed so limitless to the first white settlers who arrived on the east coast of the continent in the 17th century. The trees grow on and on, sometimes rising more than 200 feet high, with diameters up to 10 feet, and falling only after hundreds or even a thousand years. When they fall, the trees rot on the damp moss of the forest floor and return to soil to feed more trees, which grow in rows upon their nursery trunks.

The rivers of the great coastal forests bring home runs of big salmon, clogging in spawning season like a busy sidewalk at rush hour. The fish spawn only once, returning by a precisely tuned sense of smell to the streams where they were hatched from 2 to 5 years before. When the fertilized eggs have been left in the stream gravel, the fish conveniently die on the beach, making a smorgasbord for bears and other forest animals. The huge Kodiak brown bear, sometimes topping 1,000 pounds, owes everything to the millions of salmon that return to the island each summer. By comparison, the grizzly bears of the Interior -- the same species as browns, but living on grass, berries, and an occasional ground squirrel -- are mere midgets, their weight counted in the hundreds of pounds. Forest-dwelling black bears grow to only a few hundred pounds.

Boreal Forest

Rainforest covers only a small fraction of Alaska. In fact, only a third of Alaska is forested at all, and most of this is the boreal forest that covers the central part of the state, behind the rain shadow of coastal mountains that intercept moist clouds off the oceans. Ranging from the Kenai Peninsula, south of Anchorage, to the Brooks Range, where the Arctic begins, this is a taiga -- a moist, subarctic forest of smaller, slower-growing, hardier trees that leave plenty of open sky between their branches. In well-drained areas, on hillsides and southern land less susceptible to permafrost, the boreal forest is a lovely, broadly spaced combination of straight, proud white spruce and pale, spectral paper birch. Along the rivers, cottonwoods grow, with deep-grained bark and branches that spread in an oaklike matrix -- if they could speak, it would be as wise old men.

Forest fires tear through Alaska's boreal forest each summer. In the newly warmed climate, million-acre fires have become common. It's impossible to fight that much fire. Alaska has always allowed fire to take its course unless structures or certain resources are at risk. In most cases, forest managers do no more than note the occurrence on a map.

This is the land of the moose. They're as big as large horses, with a long, bulbous nose and huge eyes. Their flanks look like a worn-out shag carpet draped over a sawhorse. But moose are survivors. They thrive on land that no one else wants. In the summer, they wade out into the swampy tundra ponds to eat green muck. In the winter, they like nothing better than an old burn, where summer lightning has peeled back the forest and allowed a tangle of willows to grow -- a moose's all-time favorite food. Eaten by wolves, hunted and run over by man, stranded in the snows of a hard winter, the moose always come back.

In the summer, moose disperse and are not easily seen in thick vegetation. In the winter, they gather where walking is easy, along roads and in lowlands where people also like to live. Encounters happen often in the city, until, as a resident, you begin to take the moose for granted, or see them as a pest that eats decorative plantings and blocks bike trails. Then, skiing on a Nordic trail one day, you round a corner and come face to face with an animal that stands 2 feet over you. You can smell the beast's foul scent and see his stress, the ears pulled back on the head and the whites of the eyes showing, and you know that this wild creature, fighting to live until summer, could easily kill you. In light of a recent attack, state wildlife biologist Jessy Coltrane said, "Assume that every moose is a serial killer standing in the middle of the trail with a loaded gun."

Light & Darkness

There's no escaping the stress of winter in Alaska -- not for moose or people -- nor any shield from the exhilaration of the summer. In summer, it never really gets dark at night. In Fairbanks in June, the sun sets in the north around midnight, but it doesn't go down far enough for real darkness to settle, instead rising again 2 hours later. It's always light enough to keep hiking or fishing, and, in clear weather, it's always light enough to read. You may not see the stars from early May until sometime in August. Visitors have trouble getting used to it: Falling asleep in broad daylight can be hard. Alaskans deal with it by staying up late and being active outdoors.

In the winter, on the other hand, you forget what the sun looks like. Kids go to school and come home in the dark. The sun rises in the middle of the morning and sets after lunch. At high noon in December, the sun hangs just above the southern horizon with a weak, orange light, a constant sunset. Animals and people go into hibernation.

As you go north, the change in the length of the days gets bigger. In Ketchikan, the longest day of the year, on the June 21 summer solstice, is about 17 hours, 20 minutes; in Fairbanks, 22 hours; and in Barrow, the longest day is more than 2 months. In contrast, at the North and South poles, the sun is up half the year and down the other half.