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THE Glacier Thread (merged)

Re: Iceberg bigger than Manhattan breaks from Greenland glac

Unread postby basil_hayden » Thu 19 Jul 2012, 19:56:57

Along the same line of thinking as Dino, my first thought as I saw this on TV was "I'd like to go camping on that".
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When Glaciers Fall

Unread postby WildRose » Tue 21 Aug 2012, 23:40:25

Recently, in Jasper National Park, Alberta, at the Mount Edith Cavell site, an estimated 50 to 60% of Ghost Glacier fell from the mountain down into a pond at the base of the rock face, creating a mini-tsunami of ice, water, rock and debris that flooded the kettle's pathways and carried on down the slope to the parking lot and for a distance down Cavell Road. There are some good photos at the link below:

http://www.examiner.com/article/ghost-g ... ional-park

This is a breathtaking place and a popular tourist spot, which can be reached by driving up a mountain road full of switchbacks. The area includes gorgeous hiking trails, meadows and lakes, and the glacier kettle where the ice fell. Many people visit here every day in the summer especially. It's one of our family's favorite spots in Jasper and we have hiked there on numerous occasions. We have seen some small avalanches there on a couple of our visits.

Ghost glacier fell on August 10th in the wee morning hours. On August 9th, some visitors to the area took some video of what appears to have been a precursor event:

http://www.youtube.com/watch?v=_j183_fSLz4

Of course, the tons of ice that fell on August 10th was a much larger event, but it appears that no one was around then, which was a good thing because if it had happened in the afternoon, hundreds of people could have been casualties.

So, I've been searching for material about glaciers and climate change, what happens to cause a glacier to fall off a mountain, etc. and have found some information at Natural Resources Canada:

http://www.nrcan.gc.ca/earth-sciences/c ... ystem/2539

It seems, though, that we're in kind of uncharted territory. Parks Canada won't open the area to the public until an investigation is completed regarding the safety issues: the damage to the road, the new runoff areas formed by the tsunami of debris, a geological assessment of the glacier.

Which leads to my questions, which I direct to anyone on this forum who knows anything about this: How is a geological assessment of the glacier done? How can it be determined if the rest of this glacier is stable, or if the other glaciers on the mountain are stable? Smaller runoffs and avalanches are frequent occurrences there, so it doesn't seem that one could predict with any certainty which small avalanche might lead to a large event. The official comment from the Parks people for the moment is that they don't know what caused the glacier to fall. Jasper has experienced a very warm summer this year.

Any insights/knowledge would be appreciated! I'll keep watching for information in the news as time goes on.

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Re: When Glaciers Fall

Unread postby rockdoc123 » Wed 22 Aug 2012, 09:17:59

A bit of confusion here I think.
The video which you suggest captures a precursor event is actually a snow avalanche, very common from hanging glaciers or for that matter steep mountain sides in the spring. The only relationship this would have to the large part of ghost glacier that calved off is they are both ultimately dependent on gravity.
Hanging glaciers have considerably larger stresses within the ice sheets which are created by the generally steeper nature of their toe regions. Transverse crevasses which might form throughout the glacier as a product of extensional stresses are also paths for meltwater. If those crevasses become terminal (i.e. completely disconnect the down-dip toe of the hanging glacier from the updip cirque wall portion then it is simply a matter of gravitational forces of the detached toe being able to overcome any frictional resistance along the base of the toe. In valley glaciers this isn't a big deal but in hanging glaciers it is, hence the catastrophic collapse.
Remember also that glacier advance and retreat is not simply a product of temperature but is really a combination of snowfall accumulation and temperature. It is possible to have glaciers advance during warming climate if snowfall increases and they can retreat during cooling climates if snowfall accumulation decreases.
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Re: When Glaciers Fall

Unread postby WildRose » Wed 22 Aug 2012, 10:07:56

Thanks for your response, rockdoc.

The snow avalanche in the video is definitely larger than any I've seen when I've been up there, but I get what you're saying. There are other glaciers right above the site (Angel glacier is a big one, with a huge amount of ice hanging over the cliff) that would certainly be catastrophic if there was a collapse.

So, what does doing a geological assessment entail? Can it be determined if a collapse is imminent, or more likely, with any degree of accuracy? Is it reasonable to wonder if the stresses that affected Ghost Glacier could also be affecting other glaciers nearby (or in other areas of the Canadian Rockies), based on the snow accumulations of last winter and the warm temps this summer, and if these types of conditions continue in the next few years?

This hits close to home for me, so to speak.
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Re: When Glaciers Fall

Unread postby rockdoc123 » Wed 22 Aug 2012, 10:14:02

I know that Park Canada has set up monitoring stations on a number of glaciers to look at movements. Unfortunately it would be pretty difficult to monitor stress accumulation or release. Often these sorts of catastrophic failures are proceeded by increased movement or frequency of movement. I suspect that the number of glaciers they monitor is minimal as it is expensive and requires staff, both of which Environment Canada have limitations on.
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Re: When Glaciers Fall

Unread postby WildRose » Wed 22 Aug 2012, 10:27:17

Yes, and unfortunately there have recently been many job cuts at Parks Canada and also in other environmental monitoring areas in Canada, thanks to our federal government.

Of course, it would be difficult to monitor every site. At popular sites like Mt. Edith Cavell, though, I'd think it would be important to be able to determine the area is safe before opening it again.
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Re: When Glaciers Fall

Unread postby WildRose » Tue 28 Aug 2012, 22:26:59

Some excellent pictures from Jasper National Park's facebook page. Visitor safety crew is assessing the Mt. Edith Cavell area.

http://www.facebook.com/media/set/?set= ... 364&type=1
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Re: When Glaciers Fall

Unread postby WildRose » Mon 03 Sep 2012, 21:00:29

More pics, some really spectacular shots.

http://www.facebook.com/media/set/?set= ... 364&type=1

Where the glacier fell from (still 40 to 50% of it left):

http://www.facebook.com/photo.php?fbid= ... =3&theater

Path it took tumbling down the mountain face to the pond below, which caused the displacement:

http://www.facebook.com/photo.php?fbid= ... =3&theater

Aerial view of the debris leading down the access road and into a nearby lake:

http://www.facebook.com/photo.php?fbid= ... =3&theater

The whole area:

http://www.facebook.com/photo.php?fbid= ... =3&theater

I read somewhere that the portion of glacier that fell was the size of a small apartment building. Big impact!


It's looking like the area may not be opened for a long time, especially because of liability issues...
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Re: THE Glacier Thread (merged)

Unread postby Graeme » Mon 11 Mar 2013, 08:05:21

The melting of Canada's glaciers is irreversible

See Canada's glaciers while you still can. Their melting is irreversible, according to projections based on real-world data and validated by satellite images.

By the end of the century, a fifth of the Canadian ice sheet – the world's third largest – could be gone for good, raising average global sea levels by 3.5 centimetres.

If the whole ice sheet melts, it would raise the global sea level by about 20 centimetres, a fraction of the 70 and 7 metre rises expected respectively if Antarctica and Greenland each shed all their ice.

The Canadian melt seems paltry in comparison, but it becomes significant when the effects of other smaller ice fields melting are taken into account, says David Vaughan, leader of ice2sea, the European Union programme that supported the work.

"Most attention goes out to Greenland and Antarctica, which is understandable because they're the two largest ice bodies in the world," says co-leader of the study, Michiel van den Broeke of Utrecht University in the Netherlands. "But with this research we want to show that the Canadian ice caps should be included in [sea level] calculations."


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Re: THE Glacier Thread (merged)

Unread postby Tanada » Tue 27 Aug 2013, 17:04:24

In 2012, slightly-above-average winter accumulation in the Alps was offset by extreme summer ablation, yielding mass balances that were negative. In Austria, Mullwitzkees had a mass balance of -1461
mm w.e. and Hallstätter Gletscher a mass balance of -1944 mm w.e. (Fischer 2012). The Austrian Glacier inventory in 2011 examined 90 glaciers: 87 were in retreat and 3 were stationary. Average terminus change was -17 m, reflecting the continued negative mass balances of the region. In Italy, a large deposit of World War I ammunition melted out of the glacier on Ago Di Nardis Peak during August 2012. The Swiss Glacier Monitoring Network noted in 2011 92 glaciers retreating, 1 advancing, and 3 stationary. The one advancing glacier had retreated the previous five years. The 2012 data are not complete, but retreat was again dominant.

In Norway, terminus fluctuation data from 25 glaciers for 2012 with ongoing assessment indicate 21 retreating, 2 stable, and 2 advancing. The average terminus change was -12.5 m (Elvehøy 2012). The retreat rate is less than 2011. Mass balance surveys found deficits on all Norwegian glaciers.

In the North Cascades, Washington La Niña conditions during the winter led to a wet winter and a cool and wet spring. Summer was drier and warmer than normal. This led to nearly equilibrium conditions on North Cascade glaciers, with mass balance positive on five glaciers and negative on four glaciers (Pelto 2013). In southeast Alaska, the same La Niña conditions prevailed and led to the highest snow totals in several decades. Glacier snowlines were more than 100 m below average on Lemon Creek and Taku Glaciers of the Juneau Icefield indicative of moderate positive mass balance (Pelto 2013).

http://glacierchange.wordpress.com/2013 ... r-section/

Much more at the link including pictures and graphs.
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Re: THE Glacier Thread (merged)

Unread postby WildRose » Thu 29 Aug 2013, 22:56:42

Thanks, Tanada, for the link you provided - lots of good reading material there.

As an aside, I visited Mount Edith Cavell this past week and was amazed at the changes in the area since Ghost Glacier fell last year in August. The debris completely transformed the valley walkway and it is now deemed unsafe for visitors to walk there. You can still visit the area but are cautioned to stay on the high trail, with signs saying something to the effect that this could happen again and sticking to the high trail should protect visitors from debris if it should happen again, but of course the Angel Glacier is right there and is huge, and I wouldn't want to bet that being on the high trail would secure one's safety if a large portion of it fell. Apparently, the amount of ice and snow from Ghost Glacier that fell last August 10th was equivalent in mass to 1,428 city buses. Mount Edith Cavell is always a beautiful sight but it was quite eerie to see the changes and to realize the ice cave I walked in a couple years ago was completely covered by the debris of the ice collapse.

EDIT: Just wanted to add pics of the Angel Glacier Ice Cave (these are as I remember it a few years back), in case anyone is interested. The ice cave was close to the lake at the bottom of the mountain face.

https://www.google.ca/search?q=angel+gl ... 80&bih=920
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Re: THE Glacier Thread (merged)

Unread postby Newfie » Fri 30 Aug 2013, 06:42:32

Saw Extreme Ice last year at a movie hall.

Now on Internet. Good flic.

http://video.pbs.org/video/1108763899/
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Re: THE Glacier Thread (merged)

Unread postby WildRose » Tue 08 Oct 2013, 11:11:44

This is a recent article I found interesting about the role of warming ocean water in ice shelf melt in Antarctica:

http://news.psu.edu/story/287448/2013/0 ... r-movement

From the article:

"The researchers believe that the interaction of the ocean beneath the ice shelf and melting of the ice shelf is an important variable that should be incorporated into the sea level rise models of global warming. Other recent research shows that without the channelized underbelly of the ice shelf and glacier, melting would be even more rapid.

"The Antarctic has been relatively quiet as a contributor to sea rise," said Anandakrishnan. "What this work shows is that we have been blind to a huge phenomenon, something that will be as big a player in sea level rise in the next century as any other contributor."
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Re: THE Glacier Thread (merged)

Unread postby WildRose » Sun 13 Oct 2013, 14:54:02

Newfie wrote:Saw Extreme Ice last year at a movie hall.

Now on Internet. Good flic.

http://video.pbs.org/video/1108763899/


Thanks for that, Newfie.

Here's the site founded by James Balog, called Extreme Ice Survey. Cool time-lapse photography, etc.

http://extremeicesurvey.org/
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Re: THE Glacier Thread (merged)

Unread postby Graeme » Tue 06 May 2014, 19:42:07

International team maps nearly 200,000 global glaciers in quest for sea rise answers

An international team led by glaciologists from the University of Colorado Boulder and Trent University in Ontario, Canada has completed the first mapping of virtually all of the world's glaciers—including their locations and sizes—allowing for calculations of their volumes and ongoing contributions to global sea rise as the world warms.



The total extent of glaciers in the RGI is roughly 280,000 square miles or 727,000 square kilometers—an area slightly larger than Texas or about the size of Germany, Denmark and Poland combined. The team estimated that the corresponding total volume of sea rise collectively held by the glaciers is 14 to 18 inches, or 350 to 470 millimeters.

The new estimates are less than some previous estimates, and in total they are less than 1 percent of the amount of water stored in the Greenland and Antarctic ice sheets, which collectively contain slightly more than 200 feet, or 63 meters, of sea rise.


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Re: THE Glacier Thread (merged)

Unread postby Keith_McClary » Tue 06 May 2014, 21:55:34

Graeme wrote:phys.org

"A lot of people think that the contribution of glaciers to sea rise is insignificant when compared with the big ice sheets, ... But in the first several decades of the present century it is going to be this glacier reservoir that will be the primary contributor to sea rise. ..."
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Re: THE Glacier Thread (merged)

Unread postby Subjectivist » Wed 07 May 2014, 06:53:22

It is the area vs volume effect, mountain glaciers have a high area to volume ratio compred to ice sheets. This makes it much easier to melt a glacier than an ice sheet when all other factors ate equal.
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Columbia Glacier

Unread postby Tanada » Tue 09 Dec 2014, 08:08:21

For those who do not know Columbia glacier is a tidewater glacier in Alaska much like Jacobshavn glacier in Greenland. The glacier travels down from high altitude in the mountains from a vast ice field, then starts floating on the water in the Fjords before breaking off into ice bergs and floating away. Columbia glacier was stable from its original mapping in the 1790's right up until 1980. Since 1980 it has been shrinking, both in altitude and in length. It is one of the locations highlighted in Chasing Ice by James Blalog in his time lapse photographic essay.

Check out this series of satellite images mostly from July of different years from 1986-2014. There are some other months because a lot of the time the glacier is overcast or a satellite is not available to take a picture on a day when viewing is optimum.

http://earthobservatory.nasa.gov/Featur ... .php?all=y

It is now predicted that at the current rate the floating portion of the glacier will have completely dissipated by July 2020.

To better characterize recent changes to the Columbia Glacier, Ryan Casotto (University of New Hampshire) and colleagues used ground-based radar to measure the glacier's speed every three minutes for eight days in early October 2014. Preliminary results show that both the West Branch and the East Branch (which feeds into the Main Branch) are now moving between 5 and 10 meters (16 and 33 feet) per day. That's slow for Columbia, but fast compared to other glaciers.

Meanwhile, the area of the Main Branch hasn't changed much since 2012, but this part of the glacier is changing in other ways. The October 2014 field research found a connection between the motion of the Main Branch and the region's tides.

"That tells me that the glacier has thinned so much now and has very little traction against the bed, so that even the up and down tidal motion changes how the glacier is flowing," O'Neel said.

The tides are affecting the glacier as much as 12 kilometers (7.5 miles) upstream. The tidal effect only dissipates where the glacier bed rises above sea level and the ice-ocean connection is lost.

"This behavior makes us think that the Main Branch is once again unstable and possibly due for an episode of very rapid terminus retreat,” Pfeffer said. “It's hard to say how soon or likely that retreat is, however, and we've been surprised before."


Basically the floating portion of the glacier will retreat onto land over the next 5 years, after that it will be a 'normal' mountain glacier feeding a river of melt water that flows into the fjord. Once that happens the tourist glacier calving industry will be over.
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Re: Columbia Glacier

Unread postby sunweb » Tue 09 Dec 2014, 08:19:33

Tanada - it is happening everywhere. Here are glaciers and drought, two sides of the same coin.
http://sunweber.blogspot.com/2014/08/ph ... d-now.html

http://sunweber.blogspot.com/2014/08/th ... hotos.html
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Re: Columbia Glacier

Unread postby ROCKMAN » Tue 09 Dec 2014, 08:37:40

T - First, thanks...cool site I didn't know about. And as the article says: "The retreat of the Columbia contributes to global sea-level rise, mostly through iceberg calving. This one glacier accounts for nearly half of the ice loss in the Chugach Mountains. However, the ice losses are not exclusively tied to increasing air and water temperatures." It doesn't go into enough detail. The glacier feeds off of the Columbia Ice Field In Alberta. I've been lucky enough to walk up on top of the CIF a couple of times. From there you can see the markers denoting where the edge was as it began its retreat long before the industrial revolution began and meaningful GHG production. The CIF is actually a triple divide: melt water ultimately flows in the Pacific, Arctic and southward across the US.

And the article may be right: climate change might accelerate the melt. Or, if one understands glacial accretion dynamics, CC might actually cause the CIF to stop retreating and even grow. Likewise the retreat of the Kilimanjaro glacier isn't related to warming...it isn't melting. The loss is due to sublimation: converting to a gaseous phase directly from the solid phase. Researchers have concluded that it's primarily the result of agricultural activity around the mountain. The ag is locking up moisture and drying the air that ascends the mountain. The drier air is escalating the sublimation.

Climate change is affecting all the systems to one degree or another. Just more complex than just the notion of warmer air regardless of the origin.
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