The most common disasters result from meteorological (weather-related) and geological events and can affect any area of the U.S. Their impact can be localized or widespread, predictable or unpredictable. Damage can range from minimal to major. Depending on the severity of the incident, they can have a long-term impact on the infrastructure (roads, bridges, and utilities) of any location.

Threats involving natural forces include thunderstorm, flood, tornado, hurricane, winter storm, drought, wildfire, landslide, earthquake, tsunami (tidal wave), volcano, and dam failure. Technological (man-made) hazards include hazardous material releases and spills, acts of terrorism, and nuclear accidents. Natural hazards are usually, but not always, more predictable than any other type of hazard. Other threats include animal health emergencies, such as outbreaks of a Foreign Animal Disease.