Why do emergency alerts sometimes sound even when a disaster is far away?

Emergency systems are designed to warn people before danger reaches them, not after it has already arrived. Because forecasts and seismic detection carry uncertainty, authorities often issue broad alerts so people have time to evacuate or prepare. A tsunami warning, for example, may cover an entire coastline even if the largest waves are expected at only some locations. This trade-off favors safety, since delayed warnings can cost lives.