Extended Abstract (560K)J4.6
Understanding the Mesoscale Processes of Flash Floods: Impacts on Prediction and Response
Matthew Kelsch, UCAR/COMET, Boulder, CO
For many years the National Weather Service has provided flash flood watches and warnings and is actively keeping data on lead-time and verification. However, forecasting and verifying flash floods lacks the objective definitions that we see with other forms of dangerous weather such as severe storms, hurricanes, and winter storms. A flash flood cannot be defined by a certain amount or intensity of rain, or a given rise in a stream. The impact of intense rainfall on the surface varies greatly from basin to basin depending on the size and other hydrologic characteristics of the basin. This makes the efforts to verify flash floods somewhat questionable.
The next big step in the science of flash flood forecasting is likely to come when high- resolution hydrologic data is merged with accurate, high-resolution rainfall information. The Flash Flood Monitoring and Prediction (FFMP) software is a step in that direction. Given that flash floods are basically floods in which the rainfall and runoff are occurring on the same time and space scales, understanding rainfall intensity and its impact on relatively small, fast-response basins is essential. With this information the warnings can become more focused in time and space. More narrowly focused warnings for these mesoscale phenomena may result more useful information to society and more appropriate response to flash flood danger.
Supplementary URL: http://www.comet.ucar.edu/class/FLOAT_2001/index.htm
Joint Session 4, Flood Hydrology, Management, and Information Systems: Near and Real-Time Management, Impacts, Forecasting, and Communication Issues (Joint with the Symp on Impacts of Water Variability: Benefits and Challenges and the 17th Conference on Hydrology)
Tuesday, 11 February 2003, 8:30 AM-12:15 PM
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