This report is the result of an inventory of available information on ground winter background signatures in the optical ranges and radar and mm-microwave radiometry. FOA/FOI reports have been searched in detail and this has been supplemented by glimpses from the international literature. It appears that the basic spectroscopic properties of snow are rather well known and there is also rather ample literature on remote analysis aspects of snow-covered terrain, at least for alpine and arctic conditions. Rather few studies in the openly available international material deal with winter background signatures from a military perspective, and the FOI/FOA material on winter signatures is rather limited lending support for the need of new studies. The report ends with some suggestions of topics for such studies.