How well can satellite observations from imagers characterize cloud cover over polar regions in winter? There have been a number of studies that have validated a satellite retrieval method through comparison with ground-based observations. With the launch of the CALIPSO lidar over two years ago, we know have a more complete data set to address the challenges of remote sensing winter polar regions using passive observations. This study will make use of collocated MODIS and CALIPSO to assess and quantify the capability of using passive observations to monitor changing cloud conditions in polar regions.