NOAA Atlas 14 Volume 12: Precipitation Frequency Estimates for Idaho, Montana and Wyoming

The National Oceanic and Atmospheric Administration (NOAA) National Weather Service’s Office of Water Prediction (OWP) has been developing and updating precipitation frequency estimates for the U.S., published as volumes of NOAA Atlas 14. NOAA Atlas 14 volumes have been funded by states and other users, on a cost-reimbursable basis, and are developed for geographic sections of the country. Precipitation frequency estimates are used by hydrologists and engineers for a wide range of design and planning activities, such as the design of drainage for highways, culverts, bridges, sewer and stormwater infrastructure, and managing and mitigating urban flooding.

The new estimates for Idaho, Montana and Wyoming are published as NOAA Atlas 14 Volume 12 and supersede estimates generated in 1973 as part of the NOAA Atlas 2 publication. The final estimates for this project area are accessible through NOAA's Precipitation Frequency Data Server, alongside previously published NOAA Atlas 14 volumes. As with all previous NOAA Atlas 14 Volumes, estimates for Idaho, Montana and Wyoming are peer reviewed and user comments during the public review process were collected and incorporated accordingly into the federally generated dataset. The NOAA Atlas 14 peer review process is integral to the generation of authoritative precipitation frequency data and maximizes the utility of the dataset for a wide range of applications.

This presentation will cover the technical steps and methodology required to develop NOAA Atlas 14 precipitation frequency estimates and supporting supplemental products, challenges posed by this project area, and the final results of the updated atlas.