Extreme storms create serious flood hazards in the Colorado Front Range (CFR), making flood risk an important aspect of state and local planning. However, in areas of steep topography such as Colorado, estimates of flood risk are highly uncertain because of the sparsity of data and the high spatial and temporal variability in precipitation. Recent multidisciplinary research has raised serious questions about the accuracy of precipitation frequency estimates currently used for flood hazard planning in Colorado and other Rocky Mountain states.

The goal of this project is to develop improved methods of estimating local risks of the extreme warm season rainfall that causes severe floods in the CFR. To be useful, the information must be accepted within the regulatory process and tailored to the needs of policy makers, floodplain administrators, and technical experts. Therefore the project has two major components: (1) to learn how scientific information and uncertainty are incorporated into flood-related decision making and regulation, and (2) to develop improved methods of estimating precipitation frequencies through meteorological analysis and use of extreme value statistics.

Participants in FY2004

• Mary Downton, PI, Project Lead
  Institut for the Study of Society and Environment, NCAR
• Melissa Crandell
  Institut for the Study of Society and Environment, NCAR