Perito Moreno Glacier

A sound reaches you before the sight does. Somewhere across the water, a slab of ice breaks loose and falls. The crack rolls over the lake like distant thunder, and the echo takes its time. Then you turn, and you see it. A wall of ice, pale blue and white, standing tall where the land runs out. It does not look quite real at first.

This is the Perito Moreno Glacier. It lies in Los Glaciares National Park, in the far south of El Calafate, in the province of Santa Cruz. The park was named a World Heritage Site in 1981. The glacier is one tongue of the Southern Patagonian Ice Field, which is among the largest masses of ice anywhere outside the north and south poles.

The glacier flows down from the mountains for roughly thirty kilometers before it meets the lake. At its front, the face of ice stretches close to five kilometers across. The wall rises around seventy meters above the water. Picture a building of twenty floors, and then picture it built entirely from ice. That is what stands before you here.

The color is the thing that holds your eye. Much of the ice is white, but deep cracks and hollows glow a strong, clear blue. This happens because the ice is very dense and very old. The weight of the glacier has pressed the air out of it over many years. Tight ice like this soaks up most colors of light and sends only blue back to your eyes.

The glacier carries the name of Francisco Moreno. He was an explorer and scientist who studied this region in the nineteenth century. People called him Perito, a word that means expert. He earned the name through his work mapping the land and helping to settle where the border between El Calafate and Chile would run.

Stand still and watch the front for a while. The glacier is never truly at rest. It pushes forward slowly, day and night, fed by snow far up in the mountains. Now and then a block breaks off the face and drops into the water below. This is called calving. Each fall throws up a sheet of spray and a ring of waves, and the sound reaches you a second or two after you see it.

There is a rare event here that pulls people from across the world. At times the glacier creeps forward until its front touches the far shore of a narrow arm of the lake. The ice then works as a dam. Water on one side has nowhere to drain, so it rises, slowly at first, then by many meters.

In the end the pressure wins. Water finds the base of the ice and carves a passage through it. The passage widens into a tunnel, and the tunnel grows into a great arch. After days or weeks the arch can hold no longer, and it falls in a roar of ice and water. This rupture keeps no schedule. It has come in some years and stayed away for others.

Most visitors reach the glacier from the town of El Calafate, about eighty kilometers to the east. From the car park, a network of steel walkways runs along the hillside that faces the ice. The paths climb and descend, so you can look at the front from high above and from close to the water, and from several angles in between. Give yourself time here, because most people stay far longer than they planned.

Dress for cold and wind, even in the middle of summer. The glacier chills the air around it. A breeze tends to slide off the ice and across the water toward the walkways, and it carries the cold with it. Bring a warm layer, and keep your camera ready, because the next block may fall at any moment.

Some visitors go further and walk on the glacier itself. Guides lead small groups onto the ice with metal spikes strapped under their boots. Others board a boat that crosses the lake and holds its place near the foot of the wall, where the ice towers high above the deck and the water is dotted with floating fragments.

When you finally leave, the sound is what stays with you. The low groan of ice in motion. The sharp crack of a block letting go. This glacier has carved and filled its valley for a very long time, and it is still at work today, patient and heavy, moving forward one quiet meter at a time.