Only 20 kilometers is left for the crack on the ice shelf Larsen C, on Antarctica, to grow before it becomes a standalone, fully detached iceberg, the size of a one-quarter of Wales. The ice shelf is about 350 meters thick, and soon it could start floating the seas. At that point it would be one of the largest icebergs ever seen. The crack is visible from satellite as the image shows.
This satellite is continuously tracking the Antarctic Peninsula where the shelf is located. The crack is about 175-kilometer-long at this point. Total size of the block is about 5000 square km. The part where the last 20 kilometers of the rift are being an area of softer ice that does not crack as easily. This will slow it down, but not stop it. It is nearly impossible to predict when the crack will reach the other sea point to fully detach from the ice shelf.
Scientists watching the berg are also interested in behavior of the rest of the ice mass, after the berg has fully detached. Will the shelf remain in one piece, or we can expect further cracks? Total sea ice in that region of Antarctica moves clock-wise and it is very possible that the iceberg is moved to the area of the Southern Ocean. How far the iceberg can drift is also matter of the depth of the ocean, which is very hard to read in those areas where ice is so thick.
It remains to hope that the weakening of the shelf will not damage glaciers – the land ice that rests on them, since they are the primary cause of sea level rise. Sea ice is already in the water, creating that effect by its mere existence.