Posted by: Rob Viens | February 2, 2013

The Beauty and Terror of Tidewater Calving Glaciers, or How Darwin Became a Hero

On the 29th of January, along the shores of the Beagle Channel, Darwin encountered one of my favorite sights – a river of ice pouring off the mountains and flowing down into the sea.  It was his first time experiencing what we now call  a “tidewater calving glacier”:

“In the morning we arrived at the point where the channel divides & we entered the Northern arm. The scenery becomes very grand, the mountains on the right are very lofty & covered with a white mantle of perpetual snow: from the melting of this numbers of cascades poured their waters through the woods into the channel. — In many places magnificent glaciers extended from the mountains to the waters edge. — I cannot imagine anything more beautiful than the beryl blue of these glaciers, especially when contrasted by the snow: the occurrence of glaciers reaching to the waters edge & in summer, in Lat: 56° is a most curious phenomenon: the same thing does not occur in Norway under Lat. 70°. — From the number of small ice-bergs the channel represented in miniature the Arctic ocean.” (Jan 29)

These tidewater calving glaciers are “rivers of ice” that flow down into the ocean and “calve” icebergs off into the sea.  I’ve always liked the use of that word – it is if they were giving birth to the icebergs.  “Tidewater” is included in their name to indicate they flow into the ocean, as compared with “freshwater” calving glaciers that end in a lake. (Since the Alaskan version of these glaciers was an area of my own research, you can be sure I’ll have more to say about calving glaciers in the future.)

Calving Glacier in the Beagle Channel (from http://www.letow.com/)

calving glacier in Beagle Channel

LeConte Glacier – my own photo of the southernmost calving glacier in the northern hemisphere, and one that I spend a lot of time working around:

LeConte Glacier

In this case, the many calving glaciers that Darwin marveled at, flowed down off what is now called the Cordillera Darwin Icefield (after you know who).  The specific reason why this particular range of mountains are named after Darwin can be traced back to the local tidewater glaciers and the events of this day in 1833.

In the case of calving glaciers – with great beauty comes great hazard.  Not only do the icebergs “birthed” by the glaciers form a potential hazard as they move about in the ater, but the very act of calving can produce some pretty intense waves.  This is what the crew, surveying in the whaleboats, found out today:

“One of these glaciers placed us for a minute in most imminent peril; whilst dining in a little bay about ½ a mile from one & admiring the beautiful colour of its vertical & overhanging face, a large mass fell roaring into the water; our boats were on the beach; we saw a great wave rushing onwards & instantly it was evident how great was the chance of their being dashed into pieces. — One of the seamen just got hold of the boat as the curling breaker reached it: he was knocked over & over but not hurt & most fortunately our boat received no damage. — If they had been washed away; how dangerous would our lot have been, surrounded on all sides by hostile Savages &deprived of all provisions.” (Jan 29)

Darwin is actually being quite modest, for it was his actions that helped save the day. FitzRoy’s account tells a more detailed story (I added the emphasis):

“Our boats were hauled up out of the water upon the sandy point, and we were sitting round a fire about two hundred yards from them, when a thundering crash shook us—down came the whole front of the icy cliff—and the sea surged up in a vast heap of foam. Reverberating echoes sounded in every direction, from the lofty mountains which hemmed us in; but our whole attention was immediately called to great rolling waves which came so rapidly that there was scarcely time for the most active of our party to run and seize the boats before they were tossed along the beach like empty calabashes. By the exertions of those who grappled them or seized their ropes, they were hauled up again out of reach of a second and third roller; and indeed we had good reason to rejoice that they were just saved in time; for had not Mr. Darwin, and two or three of the men, run to them instantly, they would have been swept away from us irrecoverably. Wind and tide would soon have drifted them beyond the distance a man could swim; and then, what prizes they would have been for the Fuegians, even if we had escaped by possessing ourselves of canoes. At the extremity of the sandy point on which we stood, there were many large blocks of stone, which seemed to have been transported from the adjacent mountains, either upon masses of ice, or by the force of waves such as those which we witnessed. Had our boats struck these blocks, instead of soft sand, our dilemma would not have been much less than if they had been at once swept away. ” (Narratives, Robert FitzRoy)

As a result, FitzRoy honored his friend my immortalizing him (embedding him, if you will) in the very the land:

“The following day we passed into a large expanse of water, which I named Darwin Sound — after my messmate, who so willingly encountered the discomfort and risk of a long cruise in a small loaded boat.” (Narratives, Robert FitzRoy)

And he later named what (at the time) was believed to be the highest mountains in the region (right in the middle of the icefield) after his naturalist – Mount Darwin.  What a thrill it must have been for young Darwin, still just 23 years old,to first be part of a daring rescue and then to see his name on the atlas of South America.

Mount Darwin (from Wikipedia Commons)

Mount Darwin in Chile

Much of the research I conducted on calving glaciers was done by kayak (yeah, I know, it was pretty nice).  And one thing I learned never to do, was to approach too close the face of a calving glacier.  As FitzRoy noted, you can hear the thundering of falling icebergs all day and night, and the events create waves (both water and sound) that reverberate around the fjords. Some bergs even break off of the submerged face of the glacier and come rocketing out of the water – shooting up into the air before crashing back down.  It can be a powerful and humbling thing to experience. (RJV)

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Responses

  1. […] Passage and heroically saving the whale boats from a ice-generated wave in the Beagle Channel (see How Darwin Became a Hero) – really bring this point […]


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