That would be the final flights returning personnel from the Ice. The freighter and tanker have offloaded their cargo and the Coast Guard is on it's way to rescue a stuck ship. Time to button up for the winter.
At one point there was talk about keeping two or so plane loads of personnel in McM until the end of March to do some late season science. I have not seen any updates on whether that is happening. When I was there, as soon as we saw the Ice Breaker, it was time to start packing and shipping things north. The end of the season was near.