This is the first quantitative study on the fundamental physical and electrochemical processes that occur during cryoelectrolysis. Cryoelectrolysis is a new minimally invasive tissue ablation surgical technique that combines the processes of electrolysis and solid/liquid phase transformation (freezing). We measured the pH front propagation and the changes in resistance in a tissue simulant made of physiological saline gel with a pH dye as a function of the sample temperature in the high subzero range above the eutectic. Results demonstrate that effective electrolysis can occur in a high subzero freezing milieu and that the propagation of the pH front is only weakly dependent on temperature. These observations are consistent with a mechanism involving ionic movement through the concentrated saline solution channels between ice crystals at subfreezing temperatures above the eutectic. The Joule heating in these microchannel may cause local microscopic melting, the observed weak dependence of pH front propagation on temperature, and the large changes in resistance with time. In addition, we observed that the pH front propagation from the anode is more rapid than from the cathode. The explanation is the electro-osmotic flow from the cathode to the anode. The findings in this paper may be of fundamental value for designing future cryoelectrolytic ablation surgery protocols.