The initial several weeks of the Antarctica campaign were the most intense... at least for now. The divisions of the First Army steadily moved south, fighting through the swiftly growing swarms of Nightmare Creatures and establishing strategic encampments along the way. These encampments were going to serve as the transit points of the evacuation networks soon.
Moving through them, all the population of the Antarctic Center was going to be relocated to the siege capitals to await eventual salvation. The same thing, only on a much larger scale, was happening in East Antarctica, where most people of the Southern Quadrant lived.