Perito Moreno Glacier

The three top attractions in Patagonia are: the Cerro Torre / FitzRoy range in the northern section of Parque Nacional Glaciares, the Perito Moreno Glacier in the southern section of the Parque Nacional Glaciares, both in Argentina, and the Parque Nacional Torres del Paine in Chile.

In a previous blog post, we wrote about a hike to Cerro Torre, this blog is about attraction number two: the Perito Moreno Glacier, let’s call it PMG for short. The PMG is a tremendously popular attraction located 80 km outside of El Calafate; extremely popular because it’s stunning, and also as it is very easily accessible: you can fly into El Calafate, take a bus to the glacier, view it from the nicely done walkways, and be back at your hotel in time for a cocktail.


We were expecting crowds and booths selling kitschy crap, but we were pleasantly surprised. The walkways that face the glacier are extensive, and as soon as you have walked 10 – 15 min away from the main visitor center, the crowds disappear.

The PMG melting into Lago Argentina

And not being in the midst of a crowd is a key issue; enjoying the glacier is a visual experience, but also an auditory one. The PMG is one of the few glaciers in the world that is advancing, and in the case of PMG rather rapidly: 2m per day. The rapid advancement leads to a great deal of action, and associated noise: the glacier snaps, crackles, and pops. Large pieces fall off from the top – 60m above the lake that it is advancing into – and fall into the water with a boom; stress is relieved somewhere inside the glacier with a sound like a huge shotgun; large pieces slide into the lake water with a woosh. It’s very cool to sit and just listen and watch the glacier. And the weather was spectacular.

How's this for a lunch spot?

But wait, there’s more…

The day after our visit to the PMG, Karen and I were walking out of our campground on our way to take a nice, lengthy hike, when the owner (manager?) of the campground we were staying at came running up to us.

Great campground; great manager.

Her English was non-existent, and our Spanish needs some serious work, but after a few minutes, she conveyed to us that something unusual was happening to the PMG. We understood “7 meters” and “spectacular”, but she was so insistent that we decided to spend another day at the PMG. And a good thing we did.

Some background: the PMG advances into, and melts into, the Lago Argentina. The PMG is situated such that it advances into a rather narrow strait that connects two parts of the lake. Periodically, as the Lonely Planet puts it in its purple prose: “17 times between 1917 and 2006”, or as normal people would say: “every 5 years”, the glacier advances all the way across this narrow strait and creates a dam.

The PMG as seen in Google Earth. Note how the PMG is advancing across the narrow strait separating the north and south part of Lago Argentina.

When this dam is in place, effectively the Lago Argentina is split into two lakes, one of which, the southern part called the Brazo Rico, has plenty of inlets, including the part of the PMG that melts into it, but no outlet. The water level builds up in the Brazo Rico until it has reached a high enough level to where the water pressure ruptures the glacier dam, and this part of the glacier collapses in a very dramatic fashion. This is what our campground host had tried to explain: the water level had reached a point at which the glacier was starting to collapse.

When we arrived for our second day at the PMG, there was a heightened sense of anticipation amongst spectators and guides, and there were four photographers from the National Park on hand.

The water in the Brazo Rico has reached a level 7m higher than in the Lago Argentina, and the glacier rupture had started. Difficult to show in pictures, but underneath one part of the glacier, a river had been created leading from the Brazo Rico into the Lago Argentina.

The newly created river can bee seen at the left edge of the PMG.

And during the day we were there, the river was steadily growing, and as it undermined portions of the glacier, they would collapse into the lake. Very cool. Per one of the guides, the river would continue to grow steadily, and it would take weeks before the water level between the two halves of the lake had equalized.

The river eventually creates a huge bridge (not our pic, from a day or two later...). The bridge in turn will collapse later.

For those who can’t get enough of the PMG, go to youtube and search for “2012 perito moreno glaciar” ; there are some very neat videos.


4 thoughts on “Perito Moreno Glacier

  1. Loved reading your post today – Incredible that you were there to witness the breaking of a glacial dam!

    • Weather has been absolutely gorgeous.; we’ve only had the feared Patagonian winds one day, and yes, they are strong…, and serious rain for less than a full day. Couldn’t have asked for better. H.

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