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
Historical data
Table 1. Historical flooding data
| Dataset | Description | Map viewer link | Data download link | |
|---|---|---|---|---|
| Historical Data | National Risk Index (NRI)[1] | NRI is a dataset and online tool built by FEMA[2] to help illustrate the risk of United States communities for 18 natural hazards. It was calculated expected annual loss resulting from hazards times social vulnerability and then divided by resilience. Both composite index of all 18 hazards as well as index for each individual hazard are given. Social vulnerability and community resilience information are also given. | Link | |
| FEMA Flood map | FEMA[2] provides flood maps for people to understand the flood risk of their community. The map can be accessed via an online viewer. | National Flood Hazard Layer Viewer | ||
| U.S. historical flood risks and costs | An interactive data tool to understand the flood cost. Flooding cost data is estimated using insurance claims from National Flood Insurance Program (data website) and FEMA's Individuals and Households Program (data website), which is also available for downloading. | Link | ||
| FEMA web disaster summaries | This dataset contains financial assistance values, including the number of approved applications, as well as individual, public assistance, and hazard mitigation grant amounts. | Link | ||
| Real-time monitoring | OpenFEMA Dataset | FEMA also provides many other open datasets on disaster information, emergency management, assistance, hazard mitigation etc. in industry standard, machine-readable formats. | Link | |
| Short-term forecast | NOAA historical flood events | |||
| Seasonal outlook | Climate Risk and Resilience Portal Data Group | Dynamical downscaled future climate projection including temperature, precipitation, and fire weather index provided by the Center for Climate Resilience and Decision Science (CCRDS) at Argonne National Laboratory[3]. Data is at a resolution of 12 km2. | Link | |
| Future projection | National water dashboard by USGS | Contains a lot of useful water information based on station data, including streamflow, surface water, ground water levels, water quality, and weather observation and forecast. | Link |
Real-time monitoring
Short-term forecast
Seasonal outlook
Long-term future projection
hydrological drought based on streamflow: https://waterwatch.usgs.gov/index.php?id=ww_drought
storm-tide monitoring: https://www.usgs.gov/special-topics/water-science-school/science/storm-tide-monitoring#overview
USGS Water data (can be requested and then downloaded): https://waterdata.usgs.gov/nwis detailed site-level data about stream flow, such as gage height, discharge, both real-time monitoring, historical information, and 7-day forecast is provided. This is the corresponding map viewer: Water watch: https://waterwatch.usgs.gov/index.php.
Map information of atmospheric and hydrologic sites: https://maps.waterdata.usgs.gov/mapper/index.html
FEMS's loss estimation: https://www.fema.gov/flood-maps/products-tools/hazus
historical flood data:
- https://www.usgs.gov/mission-areas/water-resources/science/historical-flooding
- Global Flood Database: https://global-flood-database.cloudtostreet.ai/#interactive-map Mapped the major flood events recorded by the DFO Flood Observatory since the beginning of the satellite records, using NASA's MODIS (Aqua (MYD09GA/GQ) and Terra (MOD09GA/GQ) ) satellites. Population exposure estimates are derived from overlaying the flood maps with the Global Human Settlement Layer (GHSL) population data. Precipitation estimates are also provided. (0.25deg precipitation from 1983 to 2021, derived using ML. PERCIAN)
- World Atlas of Large Flood Events 1985-2002 https://floodobservatory.colorado.edu/archiveatlas/index.htm, contains statistics of flood, such as number, duration, causes, severity, as well as consequences of flood such as fatalities, displaced and damage.
- inundation maps:
- global surface water record
Near-time monitoring
- Satellite data: MODIS https://www.earthdata.nasa.gov/learn/find-data/near-real-time/hazards-and-disasters/floods (also historical data)
- Global flood monitoring system by U Maryland: http://flood.umd.edu/. Monitor streamflow and rainfall. streamflow is calculated using hydrological model. Short-term (4-5 days) forecasting is also provided.
- NASA NRT Global Flood Mapping: https://www.earthdata.nasa.gov/learn/find-data/near-real-time/modis-nrt-global-flood-product
- NASA wildfire: https://maps.disasters.nasa.gov/arcgis/apps/sites/#/home/pages/wildfires
- NASA disasters: https://disasters-nasa.hub.arcgis.com/
- Fathom global flood map: not open-source https://www.fathom.global/product/global-flood-map/
- USGS stream gauge data
Short-term outlook:
- https://www.wpc.ncep.noaa.gov/nationalfloodoutlook/
- 1-3 day and 6-10 day weather outlook is available: https://www.nwrfc.noaa.gov/misc/hmd/hmd.php?q=1723151693 https://www.nwrfc.noaa.gov/misc/hmd/hmd.php?q=1723151693
- 10 day weather forecast: https://www.nwrfc.noaa.gov/weather/10_day.cgi
- flood hazard outlook by NWS: 7-day ahead https://www.weather.gov/owp/operations-national-fho-archive?d=2024-08-08
Seasonal forecast:
- https://www.nwrfc.noaa.gov/rfc/ 120-day forecast; provides important forecast information for PNW.
- drought outlook: https://www.cnrfc.noaa.gov/?product=cpcSDO&lat=38.234&lng=-118.666 https://experience.arcgis.com/experience/29f1122ca1cd46368a614c41de26eb53/
severe weather refers to convective storm
Flood hazard data by FEMA: https://experience.arcgis.com/experience/e492db86d9b348399f4bd20330b4b274/page/Page/?views=Effective%2CSea-Level-Dataset
FEMA flooding: https://gis-fema.hub.arcgis.com/pages/flooding https://webapps.usgs.gov/infrm/fdst/
sea level rise viewer: https://coast.noaa.gov/slr/#/layer/sce/4/-10957408.272357693/4740085.158735173/5/satellite/none/0.8/2050/interHigh/midAccretion
NWS: Day 1-8; NWS GIS viewer is a treasure.
- flood forecast: https://water.noaa.gov/
- GIS viewer provides almost everything: https://viewer.weather.noaa.gov/general#layers=42904+40090&x=-84.22612&y=44.9147&z=7&panel=layer
- graphical tropical weather outlook:
- Storm surge
climate outlooks (day 6 and above) are from CPC:
- seasonal drought outlook
- 8-14 days wildfire drought hazard
- fire weather outlooks (SPC) Day 1-8
- wildfire forecast: day 1-7
USGS Post-Fire Potential Flash Flood Impacts, so flood after fire? debris flow
CDC/ATSDR social vulnerability index
Tropical products:
Coastal change
Flooding is largely related to hurricane and then related to coastal changes
USGS coastal hazard change portal: https://marine.usgs.gov/coastalchangehazardsportal/
National hurricane center: https://www.nhc.noaa.gov/refresh/graphics_at4+shtml/102341.shtml?cone#contents
USGS Hurricane resources: https://www.usgs.gov/hurricanes
National Weather Service River Observations and Forecast: https://water.weather.gov/ahps/forecasts.php A map viewer, contains information of observations, forecast, and long-range flood outlook, as well as flood hazard warning. soil moisture, stream analysis anomaly, flood inundation.
Flood Inundation Mapping - Loss Estimation: https://fim.wim.usgs.gov/fim/https://www.usgs.gov/mission-areas/water-resources/science/flood-inundation-map-fim-libraries
ESRI disaster data: https://disasters-geoplatform.hub.arcgis.com/pages/disaster-data-layers has data for specific disasters.
Historical Evaporative stress index: https://disasters-geoplatform.hub.arcgis.com/pages/visualizing-areas-at-risk-evaporate-stress-index, 5-km, a predictive index for wildfire risk.
historical damage assessment for past hurricanes and floods: https://disasters-geoplatform.hub.arcgis.com/pages/historical-damage-assessment-database
https://global-flood-database.cloudtostreet.ai/#interactive-map
https://www.earthdata.nasa.gov/learn/find-data/near-real-time/hazards-and-disasters/floods
https://kingcountyfloodcontrol.org/flood-resources/floodplain-map/
https://www.nwrfc.noaa.gov/rfc/
Storm surge inundation map: https://gis-fema.hub.arcgis.com/apps/852ca645500d419e8c6761b923380663
NOAA storm prediction center: https://gis-fema.hub.arcgis.com/documents/b4d41dd8833e43beb689bc701d6e617d