Snow depth and meteorological data from November 2007–October 2008 from two International Trans-Antarctic Scientific Expedition (ITASE) ice core sites (Skinner Saddle and Evans Piedmont Glacier) in the Ross Sea region, Antarctica, are analysed to elucidate the controls on moisture delivery to both locations. The storm tracks associated with each major accumulation event at both sites are produced from daily back-trajectories generated from reanalysis data. Cluster analysis of these trajectories reveals that the highest frequency of accumulation days at both sites are associated with south-easterly air flow, but that high-accumulation days tend to result from fast-moving air masses with strong upper-level cyclonic vorticity. Over the study period, Evans Piedmont Glacier received most precipitation from these events, which are associated with the incursion of synoptic-scale cyclonic systems and marine moisture across the margin of the Ross Ice Shelf. Skinner Saddle also received snow from these synoptic-scale systems, but a large proportion of annual snowfall at this site was also derived from short-duration events that appear to be the result of mesocyclone development over the southern Ross Ice Shelf. The frequency and seasonal distribution of both of these mechanisms of precipitation delivery will have a marked impact on annual accumulation totals over time and consequently the interpretation of ice core records from these sites.