In addition to building safer communities through mitigation and preparedness, emergency managers face the critical challenge of predicting disasters and warning the public. Prediction involves determining the location and time at which a disaster might strike; disaster warnings apply predictive information to communicate potential threats to the public. An awareness of disaster types coupled with effective prediction technologies helps society alert its members to common and not-so-common threats. The social, cultural, and political features of human communities play a fundamental role in the success of disaster prediction and warning systems. Within communities, individual groups face the challenge of communicating and interpreting warning information. This entry discusses types of disaster and prediction methods and the warning communication process.