Kintla Glacier Retreat, Glacier National Park, Montana

There continues to be a persistent misperciption that all glaciers in Glacier National Park, Montana will be gone by 2030, I get asked that by journalists frequently, and when I point out that is not the case, they are surprised. The number of glaciers has declined from 150 to less than 30 today, and most of those are doing poorly, however, there are a few that are retreating relatively slowly and not on the verge of disappearing. This week brings another examples from National Geographic. This post focusses on why this is not going to occur using Kintla Glacier as an example. Kintla Glacier is 8 km south of the border with Canada on the north slope of Kintla Peak and drains into Medicine Bow Creek and then Kintla Lake. All of the images from Google Earth and Landsat are oriented with south at the top. kintla areaKintla Glacier is noted by Key et al (2002) and by continuing USGS reseearch to have had an area of 1.7 km in 1966 and 1.15 km2 in 2005. This is the loss of nearly a third in 40 years. Here we examine changes from 1990 to 2013 using three Google Earth images and a Landsat image from 2013 to indicate the changes in the glacier during the last two decades. The margin of the glacier in the sequential Google Earth images from 1990 (red), 2003 (orange) and 2007 (yellow) indicate the limited retreat in this period. Retreat averages 30-40 m with a glacier length averaging 500 m. The width of the glacier changed even less. Hence, this glacier has lost 5-10% of its area from 1990 to 2007. n 1990 Jon Scurlock has some exceptional images of the glacier taken in 2009 and posted Glaciers of the American West. These images indicate a glacier that has less than ideal snowcover, but significant crevassing near the main terminus and insignificant retreat from 2007. In 2013 Landsat imagery from August indicates no major retreat. Thus, this glacier is thinning and retreating, but is not poised despite its small size to disappear by 2030. kintla 1990

kintla 2003

kintla 2007

Kintla 2013

A key indicator of a glacier that will not survive current climate for long, is retreat of the upper margin and appearance of bedrock outcrops on the upper glacier (Pelto, 2010), neither is apparent here. A indicates a cliff below the main terminus, and is a good measure of the lack of retreat from this point. Point B is the end of a buttress that has not changed significantly during the 1990-2007 period indicating a lack of change in the upper portion of the glacier. The last image is a picture of the glacier from 2007 indicating a glacier that is not about to disappear in the next twenty years. This glacier will survive beyond 2030 just as Harrison Glacier will. Other glaciers in this park that continues to lose glaciers are not going to survive as long, such as Grinnell Glacier or Sperry Glacier. All of the glaciers in the region are responding to recent climate change, but not at the same rate. Further warming will certainly eliminate all of them.

Kintla Glacier 2007a

Old Sun Glacier Glacier National Park slow retreat

In Glacier National Park, MT all glaciers have been retreating. From 1850 to the present the number of glaciers has been reduced from 150 to 25. There are a few glacier such as Old Sun Glacier that have been retreating quite slowly since 1966 when the USGS maps were completed and are not disappearing anytime soon. Old Sun Glacier faces northeast and terminates at 8200 feet. This is a higher altitude than the rapidly shrinking Sperry Glacier, 7600 feet or Grinnell Glacier 6600 feet. A comparison of Google Earth images of Old Sun Glacier from the 1966 USGS map to 2009 indicate that the glacier has thinned and retreated but the majority of the glacier remains. The loss of area was noted as 12% from 1966-2005 and 14% by 2009. Below is the 1966 image, 1991 image, the strong brown line is the 1991 margin, 2003 image, 2005 image and the last two are 2009 images. The upper section of the glacier retains accumulation even in the poorest years such as 2009 and the glacier remains crevasses. The number of crevasses, slow recession and healthy accumulation zone point to a glacier that with present climate can be forecast to survive Pelto (2010). As long as a glacier maintains an accumulation zone it can survive at a reduced size. There are seven glaciers in Glacier National Park that have a consistent accumulation zone today each of these as a result is diminishing slowly,compared to the majority that have and will soon disappear.