Satellite images taken May 8 (left) and May 11 (right), three days apart in 2012. A new crack that forms a “Y” branching off to the left of the previous rift. The rift opened up at speeds of up to 80 miles per hour. Photo: University of Washington
Way back in 2012, researchers at the University of Washington saw something pretty crazy: a crack appeared in Antarctica’s Pine Island Glacier Ice Shelf. The crack, in and of itself, was nothing too spectacular, but the speed at which it opened up sure was.
“This is to our knowledge the fastest rift-opening event that’s ever been observed,” said Stephanie Olinger, the lead author in a recently-published study on the event. “This shows that under certain circumstances, an ice shelf can shatter. It tells us we need to look out for this type of behavior in the future, and it informs how we might go about describing these fractures in large-scale ice sheet models.”
The Pine Island Glacier Ice Shelf is in dire straits, much like many other glaciers. It’s the fastest melting glacier in Antarctica, and it makes up around 25 percent of Antarctica’s ice loss, which is rapidly increasing. The crack was almost seven miles long and formed at 115 feet per second, which works out to about 80 miles per hour.
The phenomenon wasn’t observed first-hand, as you probably expected, but was recorded by instruments on the ice shelf and satellite camera equipment trained on the area.
Pine Island Glacier is the fastest melting glacier in Antarctica, responsible for about 25 percent of Antarctica’s ice loss. Image: Wikipedia
Cracks in ice shelves, as I mentioned, are relatively common. They’re worrying, though, because they often are a harbinger of a shelf calving. In normal years, cracks the size of the Pine Island Glacier’s form over a longer period of time, sometimes even years. But this one proved that they can also happen in just a few seconds.
Researchers are interested in what’s happening to glaciers around the world as the planet warms. The more we know about the physics of how they move and break apart, the better we can prepare for the future.
“”Before we can improve the performance of large-scale ice sheet models and projections of future sea-level rise,” Olinger explained, “we have to have a good, physics-based understanding of the many different processes that influence ice shelf stability.”
It’s generally accepted that as global average temperatures rise, these rift-opening events will speed up.
“Glacier ice appears to act like a solid on short timescales, but it behaves like an oozing honey like liquid on longer timescales,” IFLScience explained. “While this new study does suggest that ice can shatter like broken glass, the researchers believe the crack would have formed even faster if ice behaved like a simple, brittle material.”
