Overview
Design storm selection varies widely between jurisdictions, which leads to inconsistent modeling practice and results that are difficult to compare. Many agencies still rely on legacy SCS distributions that were never intended to match modern precipitation frequency estimates.
This task committee is developing guidance for a national design storm standard: how to shape hyetographs so that they conform to NOAA Atlas depths at all durations, how to select return periods and temporal distributions, and how to transition as NOAA Atlas 15 replaces Atlas 14.
Focus areas
- Design storm shaping that is consistent with Atlas 14/15 at every duration
- Replacing outdated SCS Type distributions in local criteria
- Regional climate differences and nonstationarity
- Lessons from radar-rainfall analysis of historic storm patterns
Recent updates
Task committee formed at the February committee meeting with Mitch Heineman as lead and Constantine Karos as deputy. Members noted that NOAA expects preliminary Atlas 15 volumes for the contiguous U.S. in late 2026 to early 2027, with final release in 2027.
Milestones
- Task committee formedComplete
- Review existing federal, state and local design storm guidanceIn progress
- Draft framework for a national standardPlanned
- Align recommendations with the NOAA Atlas 15 releasePlanned
How to contribute
If your agency publishes design storm criteria, or you have worked on hyetograph shaping or radar-rainfall analysis, we would like your input.
Contact the task committee