Our study analyzed eleven RADARSAT-1 images acquired over burned and unburned boreal forests in June 2000 in order to assess their potential to map fire danger variables, like the CFFDRS FWI codes and indices. RADARSAT-1 can acquire images almost daily, but the acquisition is done under different beam modes. Fine beam mode images produced highly variable low radar backscatters. Incidence angles had a predominant effect in the day-to-day o^0 variations, but these variations were also explained by rain events and by FWI variations. It is suggested that RADARSAT-1 radar backscatters are sensitive to moisture-related variables, but there is neceesary to either correct the images for incidence angle effects or to only consider images acquiring in similar beam modes.