WASHINGTON — With the dramatic crash of an iceberg against a glacier that dislodged a massive new chunk of ice, the mysterious continent of Antarctica once again did the unexpected.
A big chunk of ice, slightly smaller than the Hawaiian island of Oahu, broke off from a place it was not supposed to and in a way that was not quite anticipated, scientists reported Friday.
The new iceberg broke off from the cooler eastern end of Antarctica, the result of tidal forces that caused a longer but thinner iceberg that stretches for 60 miles to hammer it free. The new chunk broke off a long tongue of ice that had been building for decades but is unlikely to cause future ice loss problems on the continent, scientists said.
This happened as researchers have focused attention on the western side of Antarctica, a continent about 1 1/2 times the size of the United States. Concern has grown over warmer temperatures there and especially the region's shrinking peninsula.
Remarkably, that peninsula, where last year one ice shelf was said to have been hanging by a thread, has had an unusually cool summer. It has hit pause on ice loss, said Ted Scambos, senior scientist with the National Snow and Ice Data Center.
In an interview Thursday from the western peninsula where he is working, Scambos predicted no major ice calving.
On Friday Australian researchers alerted the world to the iceberg crash with the Mertz Glacier on the other side of the continent. They said it had probably occurred around Feb. 12 or 13.
"There are some crazy things going down in Antarctica," said Mark Serreze, director of the snow and ice data center, based in Boulder, Colo. "It seems kind of weird, but weird things happen."
Scientists have been tracking climate change influence in Antarctica, a place more complicated than the Arctic. Scambos was placing instruments on the dwindling Larsen ice shelf in the peninsula to measure its disintegration in a scientific version of a death watch.
The ice loss that happened a couple of weeks ago was not due to global warming but a natural process taking place in a region that has been relatively stable over the years.
For decades the tongue of the Mertz Glacier in the eastern part of the continent has grown farther out into the water until it was about 60 miles long by 18 miles wide, said Benoit Legresy, a researcher with the LEGOS laboratory for geophysical studies in Toulouse, France.