Aircraft-based estimates of the thin-ice thickness and area fraction were made in the vicinity of the SHEBA ice station in the Beaufort Sea using a downward looking radiometer and a video camera. The radiometer, a KT-19 narrow-beam instrument, was pointed at an angle of 20 degrees to the surface while we flew at an altitude of about 100 m. A series of six surveys were made between October 1997 and May 1998. Lead fractions, mean lead widths, and thin-ice thickness distributions were calculated for 10 to 15 km legs within 40 km of the ice station and on transects from the station to the shore. Detailed comparisons with RADARSAT SAR images show good correspondence between the surface temperature and low SAR backscatter in some regions and poor correspondence in others. Summaries of the observations will be presented and methods for assimilating these and other ice thickness observations into an ice model will be discussed