Caves can form within glaciers as a result of water running through or under a glacier. They are often called ice caves, but the term more accurately describes caves in bedrock that contain ice throughout the year. Water usually forms on the glacier’s surface through melting, before flowing down a moulin (vertical to nearly vertical shafts within glaciers or ice sheets) to the base of the glacier. Glacier caves can also form as a result of geothermal heat from hotsprings or volcanic vents beneath glaciers, such as the Kverkfjöll glacier cave in Vatnajökull glacier in Iceland, or where glaciers meet a body of water, with wave action.
Glacier caves can collapse or disappear because of glacier retreat. For example, the Paradise Ice Caves on Mount Rainier in Washington had 8.23 miles of passages in 1978. However, it collapsed in the 1990s, and the section of the glacier that contained the caves retreated between 2004 and 2006. Prior to collapse, caves can be used to access the interior of glaciers for research purposes, with the study of glacier caves sometimes known as glaciospeleology. Others also serve as popular tourist attractions due to their beauty.
NASA’s Operation IceBridge is finishing up its seventh annual campaign surveying Arctic ice levels. The operation has run biannual polar expeditions, one to the Arctic and the other to the Antarctic, each year since its formation in 2009. This year’s spring survey of the Arctic wrapped up on May 22.
While Operation IceBridge uses advanced remote sensing technologies to measures ice levels, IceBridge scientist John Sonntag captured a few stunning shots of glacial moulins and crevassing during a Greenland expedition.
NASA states IceBridge’s mission is to “yield an unprecedented three-dimensional view of Arctic and Antarctic ice sheets, ice shelves and sea ice.” Annual data collected from IceBridge also helps to provide continuous polar ice data throughout the gap in data collection during NASA’s Ice, Cloud and Land Elevation Satellite (ICESat), which has not collected data since 2010. The satellite’s successor, ICESat-2, will not begin data collection until 2017.
In an article for NASA’s Earth Observatory, IceBridge project scientist Michael Studinger cited the importance of IceBridge in improving sea level rising forecasts, especially for influential annual reports such as from the Intergovernmental Panel on Climate Change (IPCC). He said, “IceBridge exists because we need to understand how much ice the Greenland and Antarctic ice sheets will contribute to sea level rise over the next couple of decades. In order to do this, we need to measure how much the ice surface elevation is changing from year to year.”
You can click here to explore some of IceBridge’s data and findings. To read more about moulins, check out this GlacierHub article about moulin ice caves.
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