Understanding common public health threats is critical in preparing for disasters and improving community resilience. Disasters can be natural (eg, earthquakes, landslides, floods, hurricanes, wildfires) or technological (ie, man-made) (eg, mass shootings, bioterrorism). Disasters caused by climate change constitute a combination of these two types-cases in which man-made actions have long-term consequences through natural disasters. After a disaster, immediate public health concerns include access to water and sanitation. Other concerns include safety and security, possible infectious disease outbreaks, mental health issues, and increased risk of human trafficking. Disease outbreaks often occur due to lack of potable water and disruption of sewage disposal systems. Mental stress and mental disorders, such as acute stress disorders and anxiety disorders, should be recognized and addressed. Chaos after disasters can overwhelm law enforcement, increasing the risk of violence and human trafficking for vulnerable populations. Disasters can have a devastating effect on health care infrastructure, increase the need for mortuary and morgue services, and increase demands on the health care system.