The Great Gorge of the Ruth Glacier is one of the most spectacular gorges on earth. At nearly 35 miles long, it feeds off the slopes of Denali and Mt. Silverthrone. Numerous forks of the glacier merge into the huge icefield known as the Don Sheldon Amphitheater (aka Ruth Amphitheater). This vast snow arena encompasses some 25 square miles. Then, with nowhere else to go, the great mass of ice is pushed down a mile-wide constriction rimmed by walls up to 5,000 feet high. With so much ice being squeezed through such a narrow slot, it’s no wonder that the glacier has been measured to be more than 3,800 feet deep and moving at a rate of over three feet per day.
The black lines in the glacier are lateral moraines, formed along the sides of the glacier. As the glacier scrapes along, it tears off rock and soil from both sides of its path. This material is deposited at the top of the glacier’s edges. Lateral moraines are usually found in matching ridges on either side of the glacier. The glacier pushes material up the sides of the valley at about the same time, so lateral moraines usually have similar heights.
EF 28-135mm @ 41mm; f/4 @ 1/8000 sec, ISO 400