Ha-Iltzuk Icefield

22 11 2012

The Ha-Iltzuk Icefield is located in the southern coast mountains of western British Columbia. The glaciers of this region are a result of the loss of ice from the Cordilleran Ice Sheet, that covered all of British Columbia and Alberta during the Pleistocene. This goes to say that the glaciers of this region are mostly affected by maritime air masses, which tells us that they receive most of their precipitation in the form of snow during the wet winter months (Oct.-Mar.) and receive little precipitation during the dry summer months.

Figure 1. In the image above the confluence where the two glaciers meet is the confluence of Silverthrone Glacier (left) and Klinaklini Glacier (right). Image of the Ha-Iltzuk Icefield courtesy of NASA Earth Observatory image of the day.

The icefield has a total area of 3600 square kilometers (1,389 square miles), making it the largest icefield in the coastal mountains south of the Alaska panhandle. The Silverthrone and Klinakilini glaciers form the two major valley glaciers of the icefield. Looking at the marginal moraines (areas of accumulating soil and rock debris) one can see how as the two glaciers meet up they form a medial moraine in the center of the confluence. These glaciers are evidence of the glacial retreat during the last 50 years. It goes without question that we have played a significant role in the change of the climate, and the increase in temperature has affected the glaciation of this region in the north western Rocky Mountains.

Glacier Mass Balance is a good way to understand the advance and retreat of glaciers, Scientists have recently used digital elevation models (DEMs) to calculate the mass balance of the Teidemann and Klinkalini glaciers of coastal British Columbia. These two glaciers are good to study because they are of relatively the same elevation, have a similar orientation and are in the same maritime climate as seen in Figure 1 and 2. In these studies change in elevation, volume and area were studied on the glaciers. The DEMs consisted of aerial photographs and satellite imagery. They found that the data was within 25 m accuracy in rural areas and 125 m in isolated areas, this is significant when interpreting their results. The DEMs for the beginning of the 20th century were composed by scanning ground and aerial photographs from the 1940’s, 60’s, 70’s and 80’s. All of the studies were conducted on 100 m elevation bands on both glaciers to provide a moderately accurate average for the glaciers.

Figure 2. The image above shows the location of the Klinaklini (Combination of Silverthrone and Klinaklini glaciers) and Tiedemann glaciers in British Columbia. PG = Prince George, V = Vancouver, BC = Bella Colla.

Another method that the scientists used to calculate mass balance was a direct method on the the glacier using a Regional Atmospheric Modeling System (RAMS). This system calculated temperature, precipitation, and evapotranspiration gradients. For each of the 100 m elevation bands these factors were estimated by the modeling system, mass balance was modeled as well using the RAMS system. From 1949 to 2009 both glaciers were found to have retreated but at significantly different rates. From the models scientists found that Klinaklini had lost an area of 5.98 square km give or take 0.57 square km, while the Tiedemann glacier had lost 42.07 square km give or take 0.29 square km for a 3 year shorter time frame. This means that the percentage of loss from the Klinaklini glacier was around 9% and the Tiedemann glacier was around 8.5% over the given time frame.

Figure 3. The above image shows the extent of the Klinkalini (top) and Tiedemann (bottom) glaciers over the study time frame 1940’s to 2000’s.

The glaciers have also lost a significant amount of volume over the 60 year time frame. Klinaklini glacier lost approximately 1.5 cubic km while the Tiedemann glacier lost approximately 20.25 cubic km from 1949-2009. Is this to say that the glacial loss is due to climate change? Results from the study have shown that on the glaciers mid-elevations accumulation has occurred causing an increase in mass of the glaciers from 2005-2009, therefore it’s questionable that human induced climate change is the number one cause for the generalized loss of glacial ice within the region. The scientists have modeled the beginning of the 21st century in this study, but predicting the future is difficult to do as the population continues to grow at a rapid rate and more and more countries are trying to achieve a “western” lifestyle. If the glaciers continue to melt at the rate they are currently it would be expected to raise the oceans by a significant amount.

References

Figure 1 ~ NASA Earth Observatory

Other Figures

Tennant, Christina, Brian Menounos, Bruce Ainslie, Joseph Shea, and Peter Jackson. “Comparison of Modeled and Geodetically-derived Glacier Mass Balance for Tiedemann and Klinaklini Glaciers, Southern Coast Mountains, British Columbia, Canada.” Comparison of Modeled and Geodetically-derived Glacier Mass Balance for Tiedemann and Klinaklini Glaciers, Southern Coast Mountains, British Columbia, Canada 82-83 (2012): 74-85. Science Direct. Web. 12 Nov. 2012. <http://0-www.sciencedirect.com.skyline.ucdenver.edu/science/article/pii/S0921818111002049&gt;.

Background Information ~ (Size, location, ect.)

http://earth.jsc.nasa.gov/EarthObservatory/HeiltskukIcefieldBritishColumbia.htm

Tennant, Christina, Brian Menounos, Bruce Ainslie, Joseph Shea, and Peter Jackson. “Comparison of Modeled and Geodetically-derived Glacier Mass Balance for Tiedemann and Klinaklini Glaciers, Southern Coast Mountains, British Columbia, Canada.” Comparison of Modeled and Geodetically-derived Glacier Mass Balance for Tiedemann and Klinaklini Glaciers, Southern Coast Mountains, British Columbia, Canada 82-83 (2012): 74-85. Science Direct. Web. 12 Nov. 2012. <http://0-www.sciencedirect.com.skyline.ucdenver.edu/science/article/pii/S0921818111002049&gt;.

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