An accurate sensitivity analysis of microwave emission and scattering to snow water equivalent (SWE) is performed by using a two layer Dense Medium Radiative Transfer Model implemented for both active and passive case. In order to evaluate the potential of the recent Cosmo-Skymed and TerrasarX missions, the study is mainly focussed on X band sensors. Model simulations have shown that an appreciable sensitivity of X-band backscattering and emission to dry snow can be found for Snow Water Equivalent higher than 70-100 mm and relatively high values of snow density and crystal dimensions. These results have been confirmed by experimental data taken from Cosmo Skymed mission and ground based multifrequency radiometers on a test site in the Italian Alps.