This paper reports the results of a field test of the hazard warning system used in rock climbing. The system is succinct; it differentiates between magnitudes of hazard; and it establishes a "warnings vocabulary." The empirical hazard response models include an "individuating factor," which influences the likelihood of injury, and the severity of injury as independent variables. The models indicate that climbers do assess a "personal" probability of injury and incorporate the hazard warning message when choosing climbing routes. Climbers of greater technical ability are more likely to climb hazardous routes, but they mitigate the likelihood of the hazardous outcome by reducing the technical difficulty of the hazardous route chosen. The response increases with the degree of hazard involved.