The very high pressures (>1 GPa) that occur during the final stages of collapse of a cavitation bubble force the liquid near the bubble wall briefly (1 ns) into a metastable state of subcooling, relative to the equilibrium phase diagram. Estimates for water show that solidification in the form of high-pressure ice particles can occur at a sufficient rate to affect the collapse. This explains a number of different phenomena associated with cavitation in water. © 1994 The American Physical Society.