Alaska Geography

The St. Elias area St. Elias Icefield

At the root of the Alaska panhandle, on the border with Canada, is a magnificent area consisting of the Wrangell, Chugach, and St. Elias mountain ranges. The area is characterized by massive glaciers and icefields punctuated occasionally by bare and jagged peaks. It is the third largest glaciated region in the world after Antarctica and Greenland.

Because of the rugged, inhospitable terrain, this area is one of the most inaccessible on earth. Vast distances limit access to those travelling by dog sled or bush plane. Rugged topography limits travel within the area to mountaineers with technical climbing skills. Scores of unclimbed peaks exist.

The area is home to several noted mountain peaks:

Mount Logan (19524')
This is the highest peak in Canada and the second highest in North America after Denali. In terms of volume, Mount Logan is the most massive mountain in the world. Its summit crowns a ridge which exceeds 17000 feet in altitude for some 13 miles. Because of its isolated inland location, it takes would-be climbers a few weeks just to approach.
Mount Saint Elias (18008')
Located on the border of Alaska and the Yukon Terretory, Mount Saint Elias is the second highest peak in the U.S. and in Canada. It has a remarkable pyramidal shape and is very difficult to climb because it is so steep. Despite that fact, the first successful climb of it was quite early, in 1897, some 28 years before than Mount Logan, because of its proximity to the ocean. Its distance from the present-day tip of Icy Bay is a mere 17 miles, which is barely a stone's throw in comparison to the rest of the region.
Mount Fairweather (15299')
Mount Fairweather is the highest point in British Columbia.

Brooks Range Brooks Range

The Brooks Range runs east and west across northern Alaska, just north of the Arctic Circle and about 200 miles south of the Arctic Ocean. Although its two highest peaks just barely exceed 9000 feet, and several more are in the 8000s, the majority of its major peaks are in the 6000s and 7000s.

By every measure except altitude, the range is truly enormous. It extends for some 700 miles from the Yukon border to the Chukchi Sea, on Alaska's west coast, near Cape Lisburne. In most places it is 80 to 110 miles wide. Its great horizontal extent separates two of Alaska's major climatic zones: the interior and the North Slope.

The scenery in the Brooks Range is most spectacular. It is a complex maze of canyons whose bottoms are usually flat with meandering and/or braided rivers and many lakes and meadows. The divides between the canyons are sometimes sheer rock walls and sometimes mellow, undulating ridges. The only road access into the range is via the Dalton Highway which transects the range on its way from Fairbanks to Prudhoe Bay on the shore of the Arctic Ocean. Only a narrow corridor of the range within hiking distance of the road can be reached via this access. The remaining 95% of the range's area is accessible only by airplane. In the summer the Brooks Range supports trekking, hunting, and river running. In early spring when the rivers are still frozen, cross-country skiing is popular.

North Slope North Slope

The North Slope is the region of Alaska north of the Brooks Range. It is treeless, as the growing season will only support tundra. It is mostly flat, with a few scattered undulations due to the freezing and thawing of the ground above the permafrost. Most of the hills in this region are therefore, in effect, frost heaves. The area is all but unpopulated by humans. Herds of caribou roam the area in the summer.

Although the area is technically a desert, receiving about 5 inches of moisture per year, few would tend to think so because of its many lakes and rivers and its extensive (non-tree) vegetation. Biogeographers have termed this type of region a "cold desert". The small quantities of water that do fall on the area as precipitation are very slow to evaporate. Much of it soaks into the ground, where it freezes the following winter. The flatness of the area results in poor drainage, hence the many thousands of lakes that cover some parts of the region. Furthermore, the North Slope is underlain by shallow bedrock, which aids in retaining groundwater.

Most of the North Slope has short mild summers, except for a few Arctic Coastal areas where the temperature rarely exceeds 40° Fahrenheit. All other seasons are brutally cold throughout the region.

Denali (Mount McKinley) Denali

Mount McKinley, the official name of what the native Athabascans called Denali, is Alaska's best known landmark. At 20,320 feet above sea level, it is the highest peak in North America and the northernmost peak that reaches over 20,000 feet. Although not quite as high in altitude as the major peaks of the Andes or Himalayas, the mountain is considered a world-class climb. Its combination of high altitude and high latitude makes it one of the coldest places on earth. Climatically, Mount McKinley is the highest mountain in the world outside of Antarctica; the summit of Mount Everest is climatically equivalent to the 13,000 foot level on Denali. With 18,000 feet, Denali also has more vertical relief than any other mountain in the world.

The native Athabascans called the mountain Denali, which means, very simply, "the great one" or "the high one". The Russians called it Bolshaya, which has a very similar meaning. It received its present name from William H. Dickey, a reporter for the New York Sun, who made a trip to Alaska in 1896 to report on the gold rush which was getting under way. While on the trip, he got into an argument with a prospector about the gold standard, which the prospector opposed but Dickey favored. As a way of getting in the last word, Dickey referred to the mountain as Mount McKinley, for William McKinley, then a candidate for President of the United States, who also favored the gold standard. Because of the number of people who read his writing in the Sun, that was the name that stuck. Most climbers and other people familiar with Alaskan history and culture strongly prefer to call it Denali regardless of what Congress decrees. Denali is a highly appropriate reflection of the mountain's stature, whereas William McKinley never travelled to Alaska and is not known to have had any interest in the mountain. Some are even offended by the mountain's present official name.

Cook Inlet, Knik Arm, and Turnagain Arm Turnagain Arm

Cook Inlet extends north and then east from the Gulf of Alaska. It divides into two arms: Knik Arm on the north and Turnagain Arm on the south, with Anchorage on the peninsula between the two. Cook Inlet and its two arms are noted for their tides. With 30 to 35 feet between the high and low tides, the Inlet has the second largest range in the world after the Bay of Fundy in Nova Scotia. The reason for this enormous tidal range is the same in Cook Inlet as in the Bay of Fundy: the length of the bay is such that the resonant frequency of the water sloshing back and forth in it is close to 12 hours, which is the frequency at which tidal forces from the moon and sun are driving it. Cook inlet is also noted for its tidal bores, which are like breaking waves rushing upchannel when the tide comes in. They are due to the fact that much of the inlet is too shallow to support normal flow of water when the tide comes in. Cook Inlet is the only place in North America where tidal bores are frequently observed. When Captain Cook explored Turnagain Arm, he observed the tidal bores, recognized the danger, and told his crew to head back out to sea. That's how Turnagain Arm got its name.

At low tide, miles of mud flats become exposed; if it were not for the occasional quicksand and possibility of tidal bores when the tide comes back in, it would be safe to walk across the entire width of the channel in some places. One would think that Turnagain Arm would be very deep because it is surrounded by mountains. However, the heavily silt-laden glacial streams drop their loads when they flow out into the calmer waters of the sea. Over the eons the silt accumulates into a mud flat which is exposed at low tide.

Valley of the Ten Thousand Smokes Valley of the 10,000 Smokes

In 1912, Novarupta, a vent on the side of Mount Katmai, erupted and sent a mass of hot ash rushing down a valley stream. When the material finally stopped moving, the valley was buried under this hot ash to depths up to 700 feet. The explosion was heard in Vancouver, British Columbia, some 1400 miles away. On nearby Kodiak Island it was as dark as night and visibility was reduced to inches. In 1916, Robert Griggs, a botanist at the National Geographic Society, became the first to set foot on the now stark and barren landscape. The hot material had vaporized the water running through the former valley floor as well as rainwater and spring water flowing into it later, creating hundreds or thousands of plumes of steam belching from fumaroles. Griggs then named it the "Valley of the Ten Thousand Smokes".

For about 20 years the valley lived up to its name. Then the ash cooled, and the flow of liquid water on the surface resumed its inexorable work. Today the Valley is mostly a barren, light peach- to salmon-colored crust of porous, spongy, brittle rock and sand. The surface is mostly flat, except where the Valley's three main rivers have eroded canyons up to 100 feet deep. The canyons are still eroding at the rate of 1½ feet per year. A small minority of geologists argue that this erosion rate is impossible; a 100-foot-deep canyon cannot possibly be eroded from a flat uneroded virgin surface in 70 years, and that the present-day valley floor did not come from the 1912 eruption. But the orthodox interpretation of the observations is that such an occurrence, although incredible, is true.

For about 40 years it was believed that Mount Katmai itself, not Noavrupta, had erupted. Then it was shown that the present-day caldera on Mount Katmai (along with its lake which is very much like Crater Lake in Oregon) formed in a collapse of the summit into the void left behind by the Novarupta eruption.

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