In situ registration of snow liquid water content for avalanche protection and snow-melt prognosis is much needed. The Time Domain Reflectometry (TDR) method is a possible method to meet this need. Laboratory comparison of the TDR-method with the dilution method shows that the TDR-method has the potential to register variations in snow liquid water content down to 1–2 vol.%. It should be possible to achieve continuous registration of snow-pack wetness with a spatial resolution down to approximately 5 cm with several sets of TDR-probes (mounted with 3 cm vertical and 5 cm horizontal distance) combined with a multiplexer and a storage unit. For application when changes in snow density are great (as with newly fallen snow) the method has to be combined with separate density determinations. The dielectric constant of night-time refrozen snow can be used for density determination.