AKAlaska Geography

The easternmost point in the United States is in Alaska. So is the westernmost, and the northernmost. Pochnoi Point on Semisopochnoi Island in the Aleutians sits just across the 180th meridian at about 179 degrees 46 minutes east longitude, which technically places it further east than anything in Maine. Amatignak Island, further down the same chain, is the westernmost. Point Barrow above Utqiagvik is the northernmost. Only the southernmost extreme, in Hawaii, belongs to another state.

The scale problem

Alaska covers 665,384 square miles, more than Texas, California and Montana added together, and about one sixth of the entire United States. Classroom maps hide this by dropping Alaska into a shrunken inset box near Baja California, which is why most Americans badly underestimate it.

Its general coastline runs 6,640 miles, longer than every other state's combined, and once you trace every bay, fjord and island the tidal shoreline reaches roughly 34,000 miles. Roughly a third of the state lies north of the Arctic Circle at 66 degrees 34 minutes. Only about a fifth of it is reachable by road at all. Juneau is the one state capital with no highway connection to the rest of the continent, so its residents arrive by ferry or by air.

Denali and the seventeen tallest

Denali stands 20,310 feet, a figure the US Geological Survey settled on in 2015 after a new survey trimmed the long quoted 20,320. Seventeen of the twenty highest peaks in the United States are in Alaska. What makes Denali unusual is not just the summit elevation but the rise: it lifts roughly 18,000 feet above the lowlands at its base, a greater vertical rise from base to top than Everest manages above the Tibetan plateau.

The mountain sits in the Alaska Range, one of several arcs of high ground. The Wrangell and Saint Elias ranges crowd the southeast corner, where Mount Saint Elias reaches 18,008 feet on the Canadian line. The Brooks Range crosses the far north and carries the continental divide, so everything on its northern flank drains to the Arctic Ocean and everything south of it eventually reaches the Bering Sea or the Pacific. The Yukon River, 1,980 miles from its headwaters in British Columbia and the third longest in North America, runs across the middle of the state to the Bering Sea and freezes solid for roughly half the year.

How much of the state is ice

Estimates put the number of Alaskan glaciers near 100,000, of which only a few thousand are named. Together they cover about five percent of the state's surface. The Bering Glacier, roughly 120 miles long, is the largest in North America. The Malaspina, a piedmont glacier that spreads out into a fan where it leaves the mountains near Yakutat, covers more ground than Rhode Island. The Hubbard Glacier is one of the few advancing rather than retreating, and it has twice surged far enough to dam Russell Fjord into a lake, in 1986 and again in 2002.

Under much of the interior and the whole North Slope lies permafrost, ground that has stayed below freezing for thousands of years and runs hundreds of metres deep north of the Brooks Range. It dictates how buildings, roads and the trans Alaska pipeline are engineered, since anything that leaks heat into the ground sinks.

Sitting on a subduction zone

The Pacific plate dives beneath North America along the Aleutian Trench, and the results are visible across the southern half of the state. On March 27, 1964, the Good Friday earthquake registered magnitude 9.2, the strongest ever recorded in North America and the second strongest recorded anywhere. Land around Prince William Sound rose as much as 38 feet in places and dropped by eight feet in others, and the tsunami it launched killed people as far south as Crescent City, California.

More than 130 volcanoes and volcanic fields have been active in Alaska over the past two million years, most of them strung along the Aleutian Arc. In June 1912 Novarupta produced the largest volcanic eruption of the twentieth century anywhere on Earth, burying a nearby valley in ash hundreds of feet deep and creating what became the Valley of Ten Thousand Smokes.

Two time zones and a date line a few miles wide

Alaska used four time zones until 1983, when the state consolidated almost everything into a single Alaska Time. The far western Aleutians, past 169 degrees 30 minutes west, stayed behind on Hawaii Aleutian Time, so the state runs on two clocks.

The sharper break is in the Bering Strait, 55 miles of water separating Alaska from Russia. Little Diomede Island is American, Big Diomede is Russian, and the two sit 2.4 miles apart with the International Date Line running between them. The clock difference across that channel is about 21 hours, which is why they are sometimes called Yesterday Island and Tomorrow Island.

The temperature and daylight records

Prospect Creek recorded 80 degrees below zero on January 23, 1971, still the lowest temperature ever measured anywhere in the United States. At the other end, Fort Yukon hit 100 degrees on June 27, 1915. Utqiagvik sees the sun stay above the horizon from about May 11 to August 1, then below it from about November 18 to January 22.

The southeast panhandle is a different climate entirely, a coastal temperate rainforest where Ketchikan collects around 150 inches of rain a year and the reporting station at Little Port Walter on Baranof Island regularly logs more than 200, making it the wettest weather station in the country.

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