Hubbard Glacier could permanently dam the entrance to Russell Fiord in as little as 10 years
From NOAA Earth Observatory: Since measurements began in 1895, Alaska’s Hubbard Glacier has been thickening and steadily advancing into Disenchantment Bay. The advance runs counter to so many thinning and retreating glaciers nearby in Alaska and around the world.
The image above, acquired by the Operational Land Imager (OLI) on Landsat 8, shows Hubbard Glacier on July 22, 2014. The image shows a close-up of the glacier’s terminus on that day. Yellow lines indicate the location of the terminus on August 1, 1978, and on July 13, 2002.
According to Leigh Stearns, a glaciologist at the University of Kansas, Hubbard’s advance is due to its large accumulation area; the glacier’s catchment basin extends far into the Saint Elias Mountains. Snow that falls in the basin either melts or flows down to the terminus, causing Hubbard to steadily grow. In addition, Hubbard is building up a large moraine, shoveling sediment, rock, and other debris from Earth’s surface onto the glacier’s leading edge. The moraine at the front gives the glacier stability and allows it to advance more easily because the ice does not need to be as thick to stay grounded. (If it is thin, it can start floating and will not necessarily advance.)
Twice in the past hundred years—in 1986 and again in 2002—the moraine has made contact with Gilbert Point and blocked the entrance to Russell Fjord. With nowhere to drain, runoff caused the water level in the fjord to rise rapidly.
The image below, acquired on July 13, 2002 by the Enhanced Thematic Mapper Plus on Landsat 7, shows the glacier the last time that it sealed the fjord. Water levels to rose 0.24 meters (0.8 feet) per day. However, the closure was temporary, as water pressure overpowered the encroaching ice and debris and burst through the natural dam, returning the fjord to normal levels.
In 2002, Stearns was attending a glaciology conference in nearby Yakutat, Alaska, a town that depends on Russell Fjord’s marine life. “Understanding Hubbard’s behavior is scientifically interesting,” Stearns said, “but it also has immediate consequences for the town of Yakutat.”
Those consequences provoked her to investigate what controls the terminus position and its advance, and to estimate when the fjord might become permanently blocked. The findings, recently accepted for publication in the Journal of Geophysical Research, explain how the mechanics at the terminus override the influence of other climate fluctuations.
One estimate suggests that the fjord could permanently close by 2025. But Hubbard’s terminus is nearly 14 kilometers (9 miles) wide, and does not advance at the same rate across its entire width. The region adjacent to Gilbert Point, where the closure would occur, advances more slowly because seawater passing through the gap constantly erodes the ice. Based on the current rate of advance at the gap, Stearns estimated that closure could occur by 2043. Stearns cautions, however, that these closure dates are “projections based on our current observations, and should be viewed with skepticism.”
References and Related Reading
Stearns, L.A. et al. (2015) Glaciological and marine geological controls on terminus dynamics of Hubbard Glacier, southeast Alaska. Journal of Geophysical Research, Earth Surface, 120.
U.S. Geological Survey (2010, December) Hubberd Glacier, Alaska.
U.S. Geological Survey (2002, June 18) Advancing Glacier Coming Close to Blocking Fiord Near Yakutat, Alaska.
Credits: NASA Earth Observatory images by Joshua Stevens and Jesse Allen, using Landsat data from the U.S. Geological Survey and Hubbard Glacier data provided by Marcy Davis of The University of Texas at Austin. Caption by Kathryn Hansen.
Believe some of the worrisome shrinking glaciers are advancing again, but we don’t get the clarion reports on it like we did when they were melting back. The last “published” data on glacial mass balances was in 2011 when things were going their way.
http://www.wgms.ch/gmbb.html
Gary, I think WGMS just changed their web address. Here’s later reports
I looked at the list of WGMS glaciers (the last 3 reports) included in the total glacial mass balances. They don’t include Hubbard Glacier, Alaska, Brüggen Glacier in Chile, (largest tidewater glaciers in the NH and SH), Peterman Glacier in Greenland. They do include Taku Glacier. The glaciers they include in their total mass balances are very limited.
I would like to see a list of the largest tidewater glaciers in the northern and southern hemispheres which have been advancing or retreating and their total mass (length, depth and area). This would include Antarctica, Greenland, Arctic islands, South America and Alaska.
There needs to be a more comprehensive monitoring of “all” glaciers of the globe. And isn’t Antarctica itself a giant glacier? There are reports that its total mass is increasing. (There are also reports that it is loosing mass). Which is it? Antarctica has approximately 95% of all the freshwater ice in the entire globe…
They don’t seem to include some of the largest advancing glaciers in the world. Am I missing something WGMS?
No need for “the warmist” to worry. If the Hubbard Glacier cuts off the Russell Fiord and its level rises then it will become the poster child for sea level rise.
Isn’t that how climate-science-by-press-release works?
The general pattern for glaciers is south facing (north facing in the southern hemisphere) glaciers are retreating, while north facing glaciers are advancing. You see this in Greenland and the Himalayas. All Antarctic glaciers outside the peninsula are north facing, so fit the general pattern.of retreat versus advance.
Increasing atmospheric temperatures can not be the cause of this, and the cause is very likely to be global cloud reductions, and hence increased surface sunlight, which will have a much greater effect on south facing slopes than north facing, and at lower latitudes versus higher latitudes.
West flowing, N American glaciers like Hubbard are generally in deep valleys and at high latitude, and hence will be relatively shaded, with increased sunlight having less effect than many other locations.
If this were retreating, I could google “Hubbard glacier,” and the first 50 or so article hits would be duplicate commentaries on the press release about global warming/climate change. But since it is advancing…there are a few articles but mostly stuff about cruises.
I noticed that too – all about cruises etc.
Can’t they just blow up Gilbert point and save the fishing industry?
Or dig a canal to bypass Gilbert Point?
These concerns all seem so silly.
I think they could. It would be money well spent compared to the billions spent on “climate Change”. Kind of like spending money to reinforce the dikes in New Orleans.
@Philip Bradley
June 22, 2015 at 5:02 pm : Okay then Philip, now that increased meridional airflow is likely causing more cloudiness in mid to high latitudes: what sort of lag time might we expect before those glaciers lengthen again? Brett
But just your wait……
Oh dear! Mr J Philip Peterson, what do dikes say when they have been reinforced? Are their clothes more fashionable? And would it be better if gays were reinforced instead? But why in New Orleans? Are those ladies somewhat special?
LOL