Flash floods can occur in nearly any area of the world. A rainfall-induced flash flood is a truly hydrometeorological event: one that depends on both hydrologic and meteorological conditions. Forecasting flash floods involves a detailed understanding of the local hydrologic features and continual monitoring of the current meteorological situation.
This module examines both the hydrologic and meteorological processes that often contribute to the development of flash flooding. Common tools and technologies that are used in flash flood monitoring and forecasting, from manual gauging systems to complex radar- and satellite-based runoff models, are explored. This module also examines the strengths and limitations of these technologies, as well as how they are likely to advance in the future.
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Define a flash flood:
- Distinguish a flash flood from a general flood
- Identify the main physical processes leading to flash floods
- Recognize the connection between precipitation intensity and runoff characteristics associated with flash floods
Explain meteorological influences on flash floods:
- Know what types of clouds produce the most intense precipitation and how precipitation intensity can vary
- Identify which factors can enhance precipitation efficiency
- Understand what factors can result in increased duration of intense precipitation
Explain hydrologic influences on flash floods:
- Apply information about the runoff processes to the flash flood problem
- Understand why certain soil textures and soil profiles may result in greater flash flood risk
- Identify which physical characteristics make a basin more prone to flash flooding
- Examine how quickly and frequently flash floods can occur in urban environments
- Describe how fires and deforestation impact the flash flood risk
Understand current technologies that are used to monitor and forecast flash flood events:
- Describe how basic manual and electronic flash flood monitoring and warning systems operate
- Explain how radar and satellite data are used within flash flood forecasting, and identify advantages and disadvantages of each
- Explain the concept of flash flood guidance and how it is calculated
- Identify when and where flash flood guidance is most appropriately used
- Recognize when and how limitations in these technologies can impact forecasts
flash flood, rainfall, runoff, causative event, ThreshR, warm rain, precipitation efficiency, reflectivity-rain rate relationship, training, precipitation duration, convective, satellite, radar, hydroestimator, flash flood guidance, FFG, Threshold runoff, distributed models, Headwater guidance, Gridded guidance, soil influences, basin influences, soil moisture, urbanization, soil texture, soil profile, fire, deforestation
October 2020 - The lesson was updated to current internet standards (mp4/html5), with no changes to content.
