A model of frost melting is developed from fundamental analysis of the heat and mass transfer. The melting model envisions three stages as the frosted surface is heated: absorption of the melt water by diffusion, accumulation of the melt water, and draining of the melt water along the surface. The three stages of melting are connected physically, but the analysis of each involves a particular set of assumptions and use of a wide range parameters and physical laws. Surface wettability enters the analysis as a factor in the draining stage. The possibility of frost slumping is expressed through a criterion based on a static force balance in which contact angel is an implicit factor.