Glacier Bay has been acclaimed the crown jewel of Southeast Alaska's Inside Passage. More than 100 alpine and valley glaciers flow from the Fairweather and St. Elias Mountain Ranges in Glacier Bay National Park. These snow-capped mountain ranges provide a dramatic backdrop to the beautiful scenery of the bay. The Fairweather/St. Elias Range is one of the highest coastal mountain ranges in the World; with many peaks over 10,000 feet, the loftiest being the 15,320-foot high Mount Fairweather. But what attracts people here are the 13 or more active tidewater glaciers, some retreating, some advancing and some "calving" giant icebergs into the picturesque fjords. These are "tidewater glaciers," because they flow all the way into the sea. They "calve" icebergs when chunks of ice break away from the glacier's face with a thunderous roar and crashes into the sea below, offering breathtaking views, photographs, and videos. Only here can you see the awesome sight of a tidewater glacier flowing from a peak three miles down to sea level. Such is the case as with Margerie Glacier, which flows from Mt. Fairweather into Glacier Bay.

Glacier Bay was originally established as a national monument on February 26, 1925, when President Calvin Coolidge signed a proclamation creating Glacier Bay National Monument. Support for the designation, more than eighty organizations strong, including the National Geographic Society and the American Association for the Advancement of Science, was spearheaded by the Ecological Society of America. Set aside to protect the glacial ecology, including the resident flora and fauna communities, geology and historical interests for public enjoyment and scientific study, the monument was about half the size of the present park and preserve. After another proclamation in 1939 added marine waters to the Glacier Bay National Monument, its expanded boundaries made it the largest element within the national park system. (Until 1980 when Wrangell-St. Elias National Park and Preserve was established.)

In 1980, Congress passed the Alaska National Interest Lands Conservation Act, which changed designation from Glacier Bay National Monument to Glacier Bay National Park and Preserve, while at the same time increasing the park’s size by 523,000 acres. The current size of Glacier Bay National Park and Preserve is 3.3 million acres and contains the largest protected marine sanctuary in the world. Today, the centerpiece of the park, the Y-shaped, 15-mile-wide, 65-mile-long bay is constantly evolving due to the advancement and retreating of ice, like a carver wielding a chisel and mallet to transform a log into a totem pole. This is exemplified by McBride Glacier, which has carved out a new fjord during its last two-decade recession, where a wall of ice once stood at Muir Inlet a short 20 years ago.

Glacier Bay has been formed due to highly active glaciation. The fastest receding glacier in recorded history, Grand Pacific Glacier, flows out of the St. Elias Mountain Range. Only 200 years ago, thousands of feet of ice covered the present day Glacier Bay. In 1794, Captain George Vancouver, sailing the H.M.S. Discovery, observed the terminus of an enormous glacier at what was then the outlet of Glacier Bay. A sheer wall of "compact solid mountains of ice" lay across the bay's entrance at Icy Strait. In 1879, the renowned naturalist John Muir, in the company of Tlingit guides, found that the massive glacier had retreated 48 miles up the bay, leaving behind a remnant interglacial spruce forest. In his field journal he wrote "stumps by the hundreds, three to fifteen feet high, rooted in a stream of fine blue mud on cobbles, still have their bark on." By 1916, the face of Grand Pacific Glacier had receded 65 miles to the bend of Tarr Inlet (the West Arm) near where it is today. Therefore, in just 200 short years, glaciation has created the beautiful 65-mile-long bay we enjoy today.


In understanding how a landscape can be transformed so dramatically, one must examine how glaciers form and how they become mobile. The genesis of a glacier occurs when conditions allow for a snowfall during the winter that is greater than the amount of snowmelt during the summer. In other words, the amount of snow falling in the high mountains exceeds the amount of snow melting. The net effect is that the annual snowpack gradually accumulates over the years, its sheer weight compresses the snow below, metamorphosing it into a dense mass of ice. The snowflakes first transforms to granular snow, which is round grains of ice, but the accumulating heaviness, will soon compress it into solid ice. Interestingly, glacial ice is so compressed that scientists actually classify it as metamorphic rock. Eventually, the gravitational pull causes the ice mass to begin flowing downhill at a rate up to 7 feet per day.

Climate plays a major role in the formation of glaciers, as well as their advancement and recession. Because of cooler summers found at its towering mountain peaks and a high amount of precipitation occurring in Alaska’s Glacier Bay National Park, this process can transpire within 30 to 50 years, resulting in one of the world’s densest mass of glaciers. By comparison, this process can take up to 3,500 years in Antarctica due to the extreme aridness found there. Furthermore, glaciers will advance under conditions of cooler average temperatures or greater precipitation, hence larger amounts of snowfall. Conversely, glaciers will recede during an increasingly warm or dry climate.

Glaciers by definition are a large mass of moving ice originating from compacted snow. They are like a slow-moving river of ice, pulled gradually downward by gravitational forces. As glaciers move downhill, they pick up and transport tons of rock and other debris like a giant snowball rolled down a gravel driveway. The resulting rock-embedded ice flow becomes abrasive like sandpaper, scouring, eroding and cutting striations in the bedrock, ultimately carving out U-shaped valleys and leaving heaps of rubble in their wake.

These long, dark bands of rocky litter being transported on or frozen within glaciers are another glacial feature called moraines. Moraines are one of several visible features common to most glaciers. The different types of moraines are classified by where the debris is being deposited. Lateral moraines are rock deposits at the sides of glaciers, whereas the terminal moraine is the deposition of sediment at the glacier’s farthest point of advance, the terminus, or snout, of a glacier. Medial moraines are ridge-shaped debris deposited down the middle of glaciers, originating from large rock outcrops, called nunataks, or from the merging of lateral moraines formed when two glaciers converge.

Another characteristic common to most glaciers, which is also due to the fact that glaciers are in motion, are the huge cracks formed on the glacier. The tremendous forces produced as the glacier flows down a steep slope or around a bend cause its brittle surface to fracture; creating giant horizontal rifts in the ice called crevasses, and vertical cascades called icefalls. Resembling a frozen waterfall, an icefall is a moving river of ice that flows over a sheer slope, or a precipitous, fast-flowing segment of a glacier having a splintered and jumbled surface. Because of the phenomenon the thicker the ice, the faster it moves, glaciers tend to move more rapidly in their center than along their edges. Therefore, crevasses are more often formed along the glaciers’ sides, where slower-moving ice progresses behind the medial movement. Because they are an indication of glacial motion, crevasses and moraines are characteristics that often help define whether a mass of ice is actually a glacier.

There are different types of glaciers primarily defined for their differences in where they are found. Mountain Glaciers form in high mountainous regions, often flowing out of icefields that extend over several peaks or even across a mountain range. They are confined by the encompassing mountain topography. Valley Glaciers, originating from mountain glaciers or ice fields, flow down out of the mountains into valleys and may be very long, often flowing down beyond the snow line, but generally above sea level. They somewhat resemble gigantic tongues, being generally larger at their terminus and smaller at the base. Valley glaciers can be thought of as a mountain glacier whose flow is confined by valley walls. Piedmont glaciers occur when steep valley glaciers flow into relatively flat plains beyond the foot of a mountain, where they spread out over the surrounding terrain to resemble the bulb end of a spoon. These broad glaciers will often recede to form a dry outwash plain or freshwater lake at their terminus. Cirque Glaciers are small circular-shaped glaciers that occupies bowl-shaped depressions occurring at the upper end of mountain valleys called cirques. Typically, they are found high on mountainsides in basins or amphitheaters near ridge crests and their width tend to be as wide or wider than their length. Hanging Glaciers, also called ice aprons, are glaciers that cling precariously to the sheer rock faces of steep mountainsides. They usually terminate at or near the top of a bluff. Similar to cirque glaciers, they tend to be wider than they are long.

The type of glacier in Glacier Bay that most people are interested in seeing are the Tidewater Glaciers. These are mountain glaciers whose terminus flow all the way into the sea and usually have an almost vertical face. Also called Fjord Glaciers because they are valley glaciers that reside in fjords. Tidewater glaciers are responsible for the formation of numerous icebergs floating in the fjords, due to a spectacular process called calving. They "calve" icebergs when huge chunks or giant columns of ice break away from the glacier's face with a thunderous roar and crashes into the sea below. This process occurs because saltwater coming into contact with the submerged terminal snout results in a higher degree of melt as compared to those parts of the glacier exposed only to air. In addition, the action of the waves causes further erosion, which accelerates the meltback of the ice, until the loosened tower of glacial ice tumbles onto itself into the ocean, creating newborn icebergs.

Any one of the slabs of blue glacial ice seen above water in Glacier Bay’s fjords is only about ten to twenty percent of the total chunk of ice, literally the "tip of the iceberg," as the rest is stoically submerged beneath the sea. Icebergs are blue because they have been so thoroughly compressed that no air bubbles are contained within the ice. Therefore, only the shortest wavelengths of light will reflect through the dense ice crystals, while the other colors of the spectrum will be absorbed. Since blue is the shortest wavelength of visible light, it is reflected and hence, the glacier ice looks blue. This blue condition indicates that it is probably from a section of the glacier that is quite old. Icebergs that have been floating in the sea for awhile will begin to melt and become porous, indicating that it is losing its density. Any ice that contains air bubbles will reflect all wavelengths of visible light, making it appear white rather than blue.


There is a multitude of ways to really enjoy the scenic beauty that Glacier Bay has to offer. One way is to take an all-day cruise into the heart of Glacier Bay, viewing magnificent tidewater glaciers along the way. Departing from the Gustavus dock early in the morning, keep a watchful eye out for breaching humpback whales as you cruise into Glacier Bay. To add information and perspective, a National Park Service Ranger accompanies the cruise as narrator/interpreter for the day. Cruising past the Marble Islands, you'll have the opportunity to observe and photograph the resident sea lions as they lounge on the rocks at the water's edge.

Named for their lion-like roar, and a thick mane-like ruff, the Steller sea lion was first described by a German naturalist-explorer, Georg Steller. They are the largest sea lions, with bulls weighing in at eighteen hundred pounds and are up to eleven feet long. The females weigh about half as much as the huge bulls, but are only two to three feet shorter. These efficient predators grow so large due to their diet of pollock, cod, herring, salmon, squid, and octopus. Other island inhabitants include harbor seals, bald eagles, horned puffins, and other seabirds. Watch the shoreline of the bay for black bear, brown bear, moose, and for mountain goats on the steep hillsides above.

You'll cruise past the entrance to Muir Inlet (East Arm) on your way to the West Arm of Glacier Bay (Tarr Inlet). The cruise is planned with plenty of time for wildlife and glacier viewing. The day-cruise vessel features top-deck viewing, comfortable interior seating and large picture windows all around on both enclosed decks so you won’t miss a thing. Advancing farther into the bay, you'll notice the transition of plant life change from lush, mature evergreen forest, to younger alder and willows, to the bare rock dotted with primitive lichens and mosses at the faces of the retreating glaciers.

Deeper within the West Arm, at the head of Tarr Inlet, you will wind your way through hundreds of seal-covered icebergs to the terminus of Grand Pacific Glacier. Grand Pacific had retreated back into Canada, where it remained until 1948, when it finally inched back into the United States. Therefore, Grand Pacific Glacier has the unique distinction of being the only tidewater glacier in Alaska that crosses an international border from time to time. After more than 80 years of separation, Grand Pacific and Margerie Glaciers are again joined together. Margerie, one of Glacier Bay’s most active tidewater glaciers, may begin to advance more rapidly now that it has been coupled with Grand Pacific again. Margerie Glacier has a very distinctive icefall; avalanches of ice resembling a frozen waterfall. Since the glacier flows at such a steep gradient, and is compressed between mountain ridges, it becomes fractured into highly photogenic disarray of crevasses and seracs as it creates a frozen cascade down the mountain. You’ll stop to look and listen as the glacier cracks and groans as it prepares to "calve" a huge chunk of ice from the face of Margerie, creating another of the many floating icebergs found in the inlet.

Heading back, you may venture into Johns Hopkins Inlet, which contains the largest concentration of harbor seals in Alaska, over 4,000! They are attracted to the safety of the iceberg-choked inlet where they can haul out on bergs, give birth, and nurture their pups. John Hopkins Inlet offers the most spectacular visual delight of ice and high peaks in the bay. A succession of high-altitude basins below a headwall of peaks, ranging from Mount Quincy Adams (13,560 feet) to Mount Crillon (12,726 feet), feeds the glaciers flowing into the inlet. The peaks seem to rise directly from the sea. Ten glaciers cascade down from towering rocky heights in the short span of 10 miles, some of which are actively calving into the tidewater. At the head of the inlet is John Hopkins Glacier, which has readvanced more than 2 miles in the past 50 years. You will also see the highly active Reid and Lamplugh Glaciers and many more. If you're fortunate, you may be able to capture a giant tower of ice calving away from the face of the glacier and tumble into the sea on video, or as a photograph. Cruising back down the bay watch for rafts of sea otters or other abundant marine wildlife.

If you're interested in getting a seal's-eye view with intimate encounters with marine wildlife, then a one-day sea kayaking adventure is for you. The guides are top-quality professionals, whose knowledge of the land, safety, and teaching skills will ensure an unforgettable adventure. No prior sea kayaking or canoeing experience is needed to enjoy this wilderness trip. Your guide will teach you efficient paddle strokes, within the first hour you'll have the hang of it, and by the end of the trip you'll be paddling like a pro. The vessels used are hard-shell, double-hulled, two person sea kayaks that are extremely stable; there is very little likelihood of tipping one over. Paddling kayaks is a silent mode of travel that often allows for getting quite close to wildlife found along the bay's shoreline. The physically fit adventurous sort will thoroughly enjoy the full-day introduction to kayak touring and learning about the natural history of the entrance to Glacier Bay.

You'll be picked up at the Gustavus dock and taken to the shores of Bartlett Cove. You'll enter the chilly waters of Glacier Bay and begin paddling north towards the Beardslee Islands Archipelago. If you're fortunate enough to glide next to a humpback whale or an orca, it will be the highlight of your entire trip. If the humpbacks are "bubble net feeding," don't get too close because it's not a good idea to be inside a "bubble net" in such a small vessel! You won't have to paddle for the entire 6 to 6_ hours, as there will be beach walks along the shore and a stop on at least one of the islands to eat lunch and to explore.

Kayak the narrow, protected wilderness waterways between the Beardslee Islands and watch for soaring eagles, moose, bear, and seals. Paddle in the forested lower inlets of Glacier Bay, home to more than 220 species of birds. You may pass by huge colonies of black-legged kittiwakes, tufted puffins, and pigeon guillemots nesting on cliff faces and rocky islands. Ask your guide to help you identify black oystercatchers, harlequin ducks, marbled murrelets, surf scoters, arctic terns, and common murres. With all these birds needing nesting sites, you would think there would be overcrowding, but fortunately, each of the species have different nesting requirements. For example, on a small rocky island off the coast, the glaucous gulls nest on the flat areas on top, tufted puffins excavate burrows in the hillside while their cousins, the horned puffins, choose nearby rock crevices. The common murres likes a cliff ledge, while the kittiwakes find the cliff face itself to be satisfactory, and the guillemots prefer being close to the sea among the rocks. After a day of kayaking, you might have sore arms, but also a greater appreciation of the magnificence that makes Glacier Bay special.

A third spectacular way of experiencing Glacier Bay National Park is by obtaining an eagle’s-eye view of the park with a flightseeing adventure. You will take off with a very experienced bush pilot to behold an overhead view of Glacier Bay’s magnificent beauty from the windows of a Cessna airplane. Fly up Glacier Bay and the over the rugged Fairweather Mountain Range. From Mount Crillion rising at 12,700 feet above sea level, to Mount Fairweather, reaching 15,300 feet above the Pacific Ocean, the range appears as the tops of gigantic, jagged snow cones ascending from the frozen domain surrounding them. Marvel at the vast quantity of tidewater glaciers cascading from these lofty heights down to the Pacific Ocean to the west and into Glacier Bay to the east. Behold Reid, Lamplugh, and John Hopkins Glaciers as they cascade into John Hopkins Inlet. View Margerie Glacier and the famous Grand Pacific Glacier forming the terminus of Tarr Inlet. Discover the birth of icebergs as they calve away from tidewater glaciers.

An alternative route would take you over the East Arm of Glacier Bay National Park, where you will see a plethora of mountain peaks, ice-fed rivers, and high-mountain glaciers inhabiting the forlorn wilderness. Free your mind of everyday clutter, allowing the light, colors, and textures that make up the Davidson and Rainbow Glaciers, to permeate your senses. Contemplate the genesis of Glaciers as you fly over the Chilkat Range, blanketed with compacted snow that has long ago turned to ice. Cruise above the Alaska Chilkat Bald Eagle Preserve, taking note of the braided Chilkat River that flows through its center, as you descend, concluding this trip by landing in Haines, Alaska.

Choose and click below for Alaskan tours that include Glacier Bay National Park and Reserve excursions:

Great Alaska Expedition

Insiders' Inside Passage Tour

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