What to know
- Increases in total and extreme precipitation raises flood risk in specific regions.
- Floods cause the second highest annual death rates among weather-related hazards, mainly due to drowning.
- Droughts also pose a public health and safety risk.
Floods and heavy rainfall
Heavy rain is happening more often nationwide and is expected to increase in all U.S. regions. Increases in both extreme precipitation and total precipitation have contributed to increases in severe flooding events in certain regions. Floods rank second in U.S. weather-related deaths, causing about 98 fatalities annually, mainly due to drowning. Flash floods and flooding associated with tropical storms result in the highest number of deaths.
After effects of extreme precipitation
Elevated waterborne disease outbreaks have been reported in the weeks following heavy rainfall, although other variables may affect these associations. Water intrusion into buildings can result in mold contamination that manifests later, leading to indoor air quality problems. Buildings damaged during hurricanes are especially susceptible to water intrusion.
Populations living in damp indoor environments experience increased prevalence of asthma and other upper respiratory tract symptoms, such as coughing and wheezing, as well as lower respiratory tract infections such as pneumonia, respiratory syncytial virus (RSV), and RSV pneumonia.
Watch a short video about how climate change can increase storms and flooding, and what communities can do to prepare
Droughts
Droughts also pose risks to public health and safety. Drought conditions may increase the environmental exposure to a broad set of health hazards including:
- Wildfires
- Dust storms
- Extreme heat events
- Flash flooding
- Degraded water quality
- Reduced water quantity
Dust storms during droughts degrade air quality, with particulates linked to increased coccidioidomycosis (Valley fever) cases in Arizona and California.
CDC resources
- Floods – get ready, stay safe during, and safeguard health after a flood.
- Mold – mold and health, cleanup efforts, and prevention of mold growth
- Asthma – guidance on asthma care before, during, and after a hurricane or flood
- Water, Sanitation, & Hygiene (WASH)-related Emergencies & Outbreaks – guidance on multiple hazards related to floods and standing water
- NIOSH Storm, Flood, and Hurricane Response – for employers and workers engaged in emergency response and recovery activities
- Flood Vulnerability and Projection Data – Tracking Portal – interactive maps, tables, and charts
- Extreme Rainfall and Drought Can Impact our Health
- Warmer Water and Flooding Increase the Risk of Illness or Injury