The results of in situ measurements of radiobrightness temperature at the frequency 1.4 GHz and soil moisture in the surface layer of the test area located in Western Siberia near Omsk are given. It is shown that at low soil moisture these data are in satisfactory agreement with the SMOS data of the levels 1c and 2. In addition, correlation analysis between the topsoil moisture provided with the SMOS, on the one hand, and the forest fire danger index derived on the basis of rainfalls and temperatures recorded by the net of weather stations located in the area of the city of Krasnoyarsk Eastern Siberia was carried out. This effort was made to investigate if the SMOS data can be used to estimate forest fire danger over the areas where no weather stations are availabe. The correlation analysis showed good relationships between SMOS soil moisture data and fire danger indices.