FloodSmart – prepare now for tomorrow Understanding flood types and the risk
Know the difference between flash floods, river floods, and coastal floods, as each poses different risks.
Flash floods
Causes - typically result from heavy rainfall over a short period, often in localized areas. They can also be triggered by dam breaks or rapid snowmelt.
Characteristics - very sudden and intense. They can occur within minutes or hours of heavy rain.
Risks - high risk of life-threatening conditions due to swift water movement. They can quickly inundate roads, homes, and vehicles.
River floods
Causes - occur when rivers overflow their banks due to prolonged rainfall, snowmelt, or upstream dam releases.
Characteristics - develop more slowly than flash floods, usually over days, allowing for more preparation time.
Risks - can affect large areas, leading to prolonged inundation. Infrastructure damage and displacement of communities are common risks.
Coastal floods
Causes - result from storm surges during hurricanes or tropical storms, high tides, or sea-level rise.
Characteristics - can lead to extensive flooding of coastal areas, often exacerbated by erosion and other factors.
Risks - damage to property, infrastructure, and ecosystems. They pose significant risks to life and livelihood, especially in low-lying coastal regions.
Understanding these differences helps in preparedness and response efforts tailored to each flood type's specific risks.