This chapter is devoted to studies of measurable radiative transfer characteristics of snow slabs such as spectral reflection and transmission functions, light fluxes at the boundaries of snow, albedo and spectral and angular light field intensity distributions in deep layers of snow. The polarization of light reflected by snow is studied as well. The radiative transfer equation is introduced and solved for the case of weakly absorbing optically thick turbid media such as snowpacks. The methods described in this section can be applied to other weakly absorbing optically thick media (e.g., clouds and foams).