I've noticed a recent increase in movement of Iceberg B22-A recently, so I thought I would give an update. I post about B22-A here instead of the Iceberg thread because it is still close enough to Thwaites to affect the sea ice that helps to stabilize Thwaites to some extent.
The GIF below shows the movement of B22-A over the past 22 months. It can be separated into three phases: 1) March 2019 to April 2020, Northward Movement; 2) April 2020 to October 2020, Westward movement (with calving from the western end); and 3) October 2020 to January 2021, Northward movement again. All three phases resulting in approximately the same distance moved, so you can see that the velocity just about doubled between each phase (12 months to 6 months to 3 months.) It is this increase in speed that is most concerning.
There is some rotation during this movement, but it hasn't resulted in a pattern yet. Alternating between clockwise and counter-clockwise rotation, the orientation hasn't changed much over time.
The second image shows three areas of shallow water that tend to keep B22-A in place. A peak on the eastern end, shallows on the western end, and another shallow to the Southwest near Bear Peninsula. One concern is that the recent calving from the older Western end of the iceberg may allow it to rotate away from the shallows. Of course, further movement to the West could also free it from the Eastern Peak.
The bathymetry under B22-A has never been accurately mapped, so it is hard to make predictions. But observing the motion over time give us clues to where the iceberg is grounding and how it might float off, or at least float far enough away to change the sea ice off of Thwaites and neighboring glaciers.