An analysis is made of the formation of a thermoerosional niche into a frozen bluff due to a storm surge on the Beaufort Sea coast. As a first attempt, the problem is treated as a one-dimensional unsteady problem in which the vertical melting front of the thermoerosional niche migrates into the frozen bluff under the thermoerosional action of breaking waves inside the surf zone during a storm. The analysis examines the temporal and shore-normal variations of the temperature and salinity of the seawater and the concentration of suspended sediment resulting from the migration of the melting front into the frozen bluff. A simple analytical solution is obtained for the case where the mean water depth during a storm is approximately constant in the neighborhood of the frozen bluff. An example computation based on the simple analytical solution indicates that the thermal driving of the ambient seawater, the mechanical driving represented by the water depth, and the duration of the storm surge are important in determining the degree of the thermoerosional niche formation into the frozen bluff. The computed results are also shown to be in qualitative agreement with available field observations.