A simple three‐fluid model has been developed to describe the critical surface structure for cases in which an abrupt density jump causes resonant absorption to be the dominant absorption mechanism. In this model, ions, thermal electrons, and superthermal electrons interact in a rarefaction wave induced by the three‐temperature equation of state and the ponderomotive force of the laser beam. Scaling laws from particle‐in‐cell calculations are used to simulate the effects of resonant absorption. The three temperatures characterizing the problem result in four distinct laser intensity regimes. Simple expressions are derived for the induced static potential, ion velocity, density, and temperature in three of these regimes. It is shown that these results agree with recent two‐dimensional simulation studies. The model provides a critical surface momentum flux condition well‐suited for implementation in a one‐dimensional implosion code.