2024 Webinar: Probable Maximum Precipitation, What is it, How is it Calculated, and How do I apply i

When:  Dec 10, 2024 from 12:00 to 14:00 (ET)
Speaker(s): Bill Kappel, Applied Weather Associates, President/Chief Meteorologist

PDH's: This webinar is eligible for 2 PDH credits.

During this webinar, Applied Weather Associates (AWA) will provide detailed discussions related to the development of Probable Maximum Precipitation and its application for dam safety.  AWA will provide detailed information regarding the history of PMP development and its use in dam safety design, the current standard of practice for calculating PMP estimates, the uncertainties, and subjective aspects of PMP, how deterministically derived PMP depths relate to risk analyses, and where climate change factors into PMP estimates and dam design.  AWA will provide specific examples of site-specific and statewide PMP studies that demonstrate the calculation process from start to finish and include examples of the results that are used as input for Probable Maximum Flood (PMF) development.  The examples will include an explanation on the proper selection of the magnitude and the spatial and temporal distribution of a major precipitation event.  Discussion on the future development of PMP and potential Federal involvement will also be provided.  Note, a companion webinar is planned that will provide training on the use of the PMP to generate the PMF, including a walk-through the rapidly evolving Army Corps’ HEC-HMS and HEC-RAS modeling processes to transform the rain into the runoff.

Key Takeaways: 
1. Understand what PMP is, where the concept came from, why we use it, and how it is calculated.
2. When should I consider a site-specific study for my location?
3. Comprehend the areas of uncertainty in the PMP development and how those affect design decisions and dam safety.
4. Discuss the application of PMP outputs and the importance of temporal and spatial patterns for PMF, what temporal rainfall distributions should we use and where do you find them?
5. How do I determine which durations are most important for my location and dam design?
6. When should I consider rain-on-snow flood runoff scenarios?
7. Learn how climate change may affect PMP estimates today and in the future.
8. Explore the integration deterministically derived PMP estimates within the risk informed decision process.