Since 1949, the Pacific tsunami warning system has provided warnings of potential danger in the Pacific basin by monitoring earthquake activity and the passage of tsunamis at coastal tide gauges. However, neither seismometers, used to detect earthquakes, nor tide gauges, used to monitor tidal fluctuations, provide data that allow accurate prediction of the impact of a tsunami at a particular coastal location. Monitoring earthquakes gives good estimates of the potential for tsunami generation, based on earthquake size and location, but gives no direct information about the tsunami itself. The tide gage measurements of tsunamis are complicated by variations in local bathymetry and harbor shapes, which severely limits the effectiveness of the data for providing useful measurements for tsunami forecasting. Tide gauges can provide verifications of tsunami forecast skill, but they cannot provide necessary data for efficient forecast itself, definitely not for the coast where they are installed. Partly because of these data limitations, 15 of 20 tsunami warnings issued since 1946 were considered false alarms because the waves that arrived were too weak to cause damage. Recently developed real-time, deep-ocean tsunami detectors (tsunameters) provide the data necessary for models to make forecasts. The deep-ocean tsunami data combined with models can provide timely and accurate forecast for coastal communities. Recent distant tsunamis demonstrated the accuracy of this observation/model technology.