An iceberg roughly twice the size of New York City is poised to break off from Antarctica’s Brunt Ice Shelf, where scientists have been living and working nearly constantly since 1956, threatening the ice shelf’s stability.
The problem resides with a massive crack working its way north as fast as 4 kilometers (2.5 miles) per year. When this crack reaches the eastward-growing “Halloween crack” that appeared in Oct. 2016, the iceberg will break off, or calve, from the ice shelf.
TU Delft satellite remote sensing expert Stef Lhermitte, who has been observing the progression of the crack known as chasm 1, told Earther there are roughly 2.5 miles to go before the iceberg calves. It’s difficult to estimate exactly when this will happen, however, as this distance could be covered in a year or mere days.
Historical Brunt ice shelf fronts since 20th century in one snapshot. Conclusion: today Brunt is exceptionally large. When it calves along Chasm 1, it will be exceptionally small. Pic.twitter.com/qkBtqTIypA
— Stef Lhermitte (@StefLhermitte) February 4, 2019
According to NASA’s Earth Observatory, the potential 1700 square kilometer (660 square miles) iceberg isn’t very large by historical standards, but it would be the largest piece to break from the Brunt Ice Shelf since observations began in 1915.
The loss of ice particularly poses a threat to the British Antarctic Survey’s Halley Station, which conducts atmospheric and geological research. The researchers used to work year-round, but the station has been forced to close twice in recent years due to unpredictable changes in the ice.
The Halley station has been rebuilt and relocated several times since its founding in the 1950s, as construction methods and geographical circumstances change. The most recent version, Halley VIa, rests upstream and to the east of the northward-growing crack in the ice shelf.