Flooding

Floods are natural disasters that occur when an area experiences an overflow of water onto normally dry land. These events can result from various causes and have significant impacts on communities, the environment, and infrastructure. Here are key aspects of floods:

Causes of Floods

1. Heavy Rainfall: Prolonged and intense rainfall can lead to the saturation of soil, exceeding its capacity to absorb water. This runoff contributes to surface water accumulation and potential flooding.

2. Storm Surges: Coastal areas can experience flooding due to storm surges, which are abnormal rises in sea level generated by storms, especially tropical cyclones.

3. Snowmelt: Spring thaw or sudden warming can cause the melting of snow, leading to increased water runoff and the potential for river or urban flooding.

6. Dam or Levee Failures: Failure of dams or levees can release large volumes of water, causing downstream flooding.

Types of Floods

4. Flash Floods: Flash floods result from intense rainfall over a short period, often in mountainous or urban areas. They can lead to rapid and unexpected rises in water levels.

5. River Flooding: Overflow of rivers and streams due to excessive rainfall or the melting of snow in upstream areas can lead to river flooding.

• Coastal Floods: Result from storm surges, high tides, or tsunamis, causing seawater to inundate coastal areas.
• Urban Floods: Occur in urban areas due to inadequate drainage systems overwhelmed by heavy rainfall.
• Pluvial Floods: Also known as surface water floods, these happen when heavy rainfall creates a flood event independent of an overflowing water body.

Impacts of Floods

1. Infrastructure Damage: Floodwaters can damage roads, bridges, buildings, and other infrastructure, disrupting transportation and utilities.

2. Loss of Lives and Property: Floods pose a significant risk to human life and property. Rapidly rising water levels can lead to evacuations and, in severe cases, loss of life.

3. Economic Impact: Flooding can have long-term economic consequences, affecting agriculture, businesses, and communities. Recovery efforts can be costly.

4. Environmental Consequences: Floods can alter ecosystems, impact wildlife, and introduce pollutants into water bodies, affecting the environment.

5. Public Health Risks: Contaminated floodwaters can pose health risks, including the spread of waterborne diseases.

Flood Data Analysis

Dataset	Description	Link
National Risk Index	The National Risk Index is a dataset and online tool to help illustrate the United States communities most at risk for 18 natural hazards. It was designed and built by FEMA in close collaboration with various stakeholders and partners in academia; local, state and federal government; and private industry.