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The states of the earth surface in terms of freeze and thaw (FT) cycles especially in high-latitude regions have a crucial role in many applications such as biogeochemical transitions, hydrology and ecosystem studies. This study uses Synthetic Aperture Radar (SAR) c-band backscatter data from Sentinel 1 from April 2014 to December 2017 to detect high-resolution freeze/thaw states in Alaska. The contrasts between frozen and thawed seasons are used to define FT states. Comprehensive in situ observations of soil temperature, air temperature, snow depth, and soil moisture were obtained to develop appropriate sigma (dB) thresholds of backscattering between freeze and thaw states. The developed thresholds were used to detect FT in Alaska, USA. The results of this method revealed that the estimates are reasonably able to detect the states of surface when compared with ground measurements from SNOw …