The Juneau Icefield straddles the Coast Mountains between Mount Hefty in the north to Devil's Paw in the south. Some of the more famous glaciers of this icefield include the advancing Taku Glacier, the massive Llewellyn Glacier which drains into Atlin Lake, the Hole-in-Wall Glacier (a tributary of the famous Taku Glacier), and the most accessible glacier, Mendenhall Glacier, which is on the southwest side of the Juneau Icefield.

The glaciated regions in North America were known to the local peoples long before scientific explorations began. The Juneau Icefield was known as the "home of the spirits" and the term nunatak, which refers to a peak protruding above the surrounding ice, is an Inuit word (Miller, 1967). Some of the early explorers of southeast Alaska include Vitus Bering, who arrived in the mid-1700s, followed by George Vancouver in 1794, and John Muir 85 years later (KTOO TV, 1987). When Muir first visited the Mendenhall Glacier in 1879 he said it was "one of the most beautiful of all the coast glaciers that are in the first stage of decadence." At this time the glacier was called the Auk Glacier after the Auks, a Tlinget tribe (the glacier is now named after Thomas Corwin Mendenhall who was the Superintendent of the United States Coast and Geodetic Survey from 1889-1894 and on the Alaska Boundary Commission). Muir's visit and other expeditions provide firsthand accounts of Mendenhall Glacier's receding nature. During a later visit at the end of June in 1890 Muir described the Auk (Mendenhall) Glacier and surrounding countryside:

"Leaving Juneau at noon, we had a good view of the Auk Glacier at the mouth of the channel between Douglas Island and the mainland, and of Eagle Glacier a few miles north of the Auk on the east side of Lynn Canal. Then the Davidson Glacier came in sight, finely curved, striped with medial moraines, and girdled in front by its magnificant tree-fringed terminal moraine; and besides these many others of every size and pattern on the mountains bounding Lynn Canal, most of them comparitively small, completing their scupture. The mountains on either hand and at the head of the canal are strikingly beautiful at any time of the year. The sky to-day is mostly clear, with just clouds enough hovering about the mountains to show them to best advantage as they stretch onward in sustained grandeur like two separate and distinct ranges, each mountain with its glaciers and clouds and fine sculpture glowing bright in smooth, graded light. Only a few of them exceed five thousand feet in height; but as one naturally associates great height with ice- and snow- laden mountains and with glacial sculpture so pronounced, they seem much higher..."

Mendenhall Glacier formed about 3,000 years ago in the Neoglacial of the Late Cenozoic Ice Age and reached its maximum during the relatively recent Little Ice Age. Since 1767 it has receded 2.5 miles (Eppenbach, 1997). Currently, the glacier is 12 miles long and terminates in Mendenhall Lake. It originates on the "western snowfields of the Taku Range" at an elevation of 5,500 feet and flows down to 100 feet above sea level (Miller, Miller, and Miller, 1987). The glacier is over 200 feet thick at its terminus, with more than 100 feet poking above the water and another 100 feet below the water's surface (KTOO TV, 1987). The glacier flows at a rate of about 2 feet per day but because it descends into a warmer, maritime climate the terminus melts faster than it grows and thus the glacier is receding (Miller, Miller, and Miller, 1987).

To get to Mendenhall glacier by air, many tourists leave from a helicopter pad a little northwest of Juneau beside the Gastineau Channel, which was carved out by ice along a fault line. Being up in the sky is so delightful!

Below Mendenhall Lake along the Mendenhall River is a community with the glacier creeping out of the mountains in the background. I was curious as to which community this was, but the helicopter soared on, bringing us ever closer and closer to the glacier. Once over the lake near the terminus of the glacier, you can see a waterfall pouring forth from between Heintzleman Ridge and Bullard Mountain.

And then, spectacular of all spectaculars, we flew over Suicide Icefall formed from another glacier flowing off the Juneau Icefield between Mendenhall Towers and Wrather Mountain (check this out). We flew further north up the glacier before heading back and landing near Suicide Icefall. Ogives or Forbes' bands are outstanding features of this icefall. The dark bands are the dirty, summer troughs and the light bands are the winter crests. A pair of light and dark bands is one year's movement over the icefall (Hambrey, 1994).

There are several prominent features on the surface of the glacier. Crevasses gash the surface of the glacier and are up to 120 feet deep on the Juneau Icefield (Miller, Miller, and Miller, 1987). Moulins are rather like vertical streams or deep, leaky potholes in the glacier filled with water.

Where the smaller glacier coming off of Suicide Icefall joins with the Mendenhall glacier, a medial moraine is formed from the fusion of two moraines (typically two lateral moraines, but in this case a lateral moraine of the Mendenhall Glacier proper and the terminal moraine of the Suicide Icefall glacier). The size of the debris on the moraine is quite variable. It was a real thrill to walk on a medial moraine! Several huge boulders were supported by columns of ice somewhat like a pedestal rock.

Alas, the helicopters returned and I took one last look across the Mendenhall Glacier to the mountains beyond before boarding the helicopter for the trip back.