Saturday, December 6, 2008

My Visit to Patagonia's Glaciers

By Graham

Three days ago I saw one of the most amazing sights.

My family and I were on a three-story boat on the waters of Lago Argentino in Patagonia. For the first time in my life I saw icebergs and glaciers. Icebergs are chunks that have fallen off glaciers. They are all different shapes and sizes. In Patagonia some are as big as houses and some are the size of a baseball.

Two hours later we saw their source: the gigantic glacier Upsala, 100 m tall, 50 km long, and 10 km wide. It towered over us. Once Upsala was the biggest glacier in South America; now, it is losing 200 m a year, due to global warming. A glacier that loses more ice than it gains is known as an unstable glacier.

We noticed that the glacier was blue. This happens when the ice becomes very dense. Years of compression slowly force out tiny pockets of air trapped between ice crystals. Extremely dense ice absorbs all other colors in the spectrum except blue, which is what we see. If glacier ice is white, it usually means lots of air is trapped inside.

Glaciers are formed when snow stays in the same place all year, and then new snow piles on top of it for years and years. The compression forces snow to recrystalize, forming grains similar in size and shape to a grain of sugar. Slowly, the grains become bigger and the air pockets between them become smaller. After two years, the snow turns into firn, which is between snow and glacier ice.

We sailed two hours to reach an even taller glacier, called Perito Moreno. Named after a famous explorer and environmentalist, the glacier is 250 square kms and one of three stable glaciers in Patagonia. It is fed by the Southern Patagonian ice field, along with 47 other glaciers.
Watching ice fall from the face of the glacier into the lake was amazing. Some of the pieces must have been the size of a house. A gigantic piece of ice would crack off the glacier and tumble into the water, creating a sound like a savage beast grumbling. It just blew thunder away. I jumped every time I heard it.

Sabias Que?
* Glaciers produce 75% of the world’s fresh water.

* Presently, 10% of land is covered by glaciers.

* During the last ice age, glaciers covered 32% of total land area.
* If all land ice melted, the sea level would rise 70 m worldwide.



Click image for larger view.

View of Perito Moreno glacier.


Graham is splashed by glacial water.


Now we know why the Titanic went down.


Hues of blue.


Hielo azul sin martini.


Only blue light is reflected from the densest ice.


Impersonation of Wall Street.

video
Video of calving ice at Perito Moreno.

5 comments:

Abuela Rosa said...

Mira !! Que informacion interesante de glacieres ! Yo no sabia tantos cosas de los.
Muy bien , Graham .Donde aprendistes esta informacion ?

Anonymous said...

Graham,
I really enjoyed your report. Keep it up! I'll share it with Andrew, Eric and Rose next.

Anonymous said...

Oh my gosh that was so interesting.
That was so cool when the big chunk of ice fell from the glacier.
From Mallory Ballance
Mrs.Rolander`s class 5th grade

Anonymous said...

We want more! Graham write more!

Therese Mageau said...

Graham -- That was a fantastic account of glaciers -- very accurate and well written. Your parents need to talk you to Alaska, where you can see more glaciers like this. Although I have to say that the blue in these Patagonian glaciers was the bluest I have ever seen. Also, I thought a glacier that gets less snow than ice melt is called a retreating glacier. Is there a difference between a retreating and unstable glacier, or are they two different words for the same thing?