In the earlier images from February and March, the northern half again 'led the way' in terms of breakup. Note also that the ice front on the November 20th image appears to have followed a crack barely visible on the February 15th image. Summertime images of this area consistently show melt ponding present in the northern half of the shelf, and absent in the southern half - so there is an implied link between extensive surface melting and breakup. Recent models by Christina Hulbe indicate that the shelf ice stiffness suggests a low internal temperature. This implies that most of the shelf ice comes from cold glacial catchment areas in the mountains of the Antarctic Peninsula.
Cold ice is stiff ice.
This stiffness is a key factor in determining its stability. For the southern Larsen B, the glacial catchments are considerably further south, and presumably cooler. Downslope winds, following the glacier troughs, are probably also cooler on average and therefore would cause less surface melt. Thus, the southern section might be more stable than the north. These features are inferred to form at the grounding line and above as part of glacier flow.