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You Can View Glaciers By Seaplane

A virtual tour with Arlene F. Harder, MA, MFT

Although my camera didn't work when we were over Knik Glacier, the man who sat ahead of me on the plane let me buy copies of his roll of film. So these are his.

I've chosen the one on the right to show you the dark stuff in the bottom of the picture. That's glacial silt that's been ground off the mountains by the slow, inexorable movement of the glacier. It gets deposited downstream when the glacier retreats as the ice melts. The silt gradually builds up and forms ground on which plants can grow, much as you can see in front of Mendenhall Glacier in the previous page.

In fact, several miles below Knik Glacier, the black and gray sediment gradually gave way to land-in-formation where moose grazed and where -- when the world's population expands enough so that lots of people will want to move to Alaska no matter how cold and dark it may get in the winter -- one day you might see homes. Of course, not all glacial silt is black because the terrain of the mountains through which a glacier moves is not always the same, as you may notice if you compare this picture with the glacier in Mendenhall Glacier. But the principle is the same.

All of this is interesting if you're a geologist. But the reason I show the picture is to discuss a most peculiar phenomenon when the sediment from a glacier meets tidewater. Then you can end up with something that is similar to quicksand, only far deadlier.

The reason? The silt consists of really weird material with grains as fine as talcum powder, although it looks like ordinary mud. But watch out, pal. When the tide is in, the mud liquefies because the water forces apart the grains of silt. Then as the tide recedes, the silt becomes firmer. Like muck. Like glue.

Only the unwary or the foolish attempt to walk across it. Trying to walk faster in an effort to get out of the stuff more quickly, their boots get stuck fast. Very soon, trying to pitch forward, then sideways, each wrench pulls them deeper as the strangely shaped particles act as a vice that presses against the body. In moments, the thick, gray gunk swallows shins and calves. They are hopelessly trapped -- unable to escape before the tide returns.

Sound gruesome? It is. Alaskan tides are among the fastest-rising and most dangerous in the world. When the water comes in, the tide can sweep across the flats, rising at a rate of one foot every twelve minutes. Even when a helicopter is brought in to rescue a hiker or hunter who has gotten caught, the person may not be able to be pulled out.

Until recently, the helicopter would hover above a person stuck in the dark and dangerous gunk. A halter would be put around his waist and he would need to use his arms to scoop out the mud, pushing it away from his body so he could free himself. But as fast as he pushed at the slime, it would pour back on him, like lava. In fact, we heard from several sources that a few years ago a woman (I believe she was on her honeymoon) got stuck and TV cameras showed her unsuccessful struggles to get out before the tide washed over her head.

Today they've devised a new method in which they use a pump to squirt water down around the body, pushing apart the grains of silt and making it easier to pull the person out. So maybe rescue is more possible than it has been, but don't risk it.

I like the picture of the Knik glacier on the left because our pilot, Jay, kept us informed of what we were seeing (we were wearing head phones so we could talk back and forth) and he made certain that people on both sides of the plane had a good view, flying first in one direction and then another. As you can see, we weren't far above the surface of the lake formed by this magnificent piece of moving ice.

Continue the tour with You Can View Glaciers by Bus

© Copyright 2000, Revised 2002, Arlene F. Harder, MA, MFT