words

Archive of past heavy precipitation events

Switch to a different threshold:

Select a year: 50 year, 24-hour recurrence interval

There were 51 dates where the rainfall exceeded the threshold in 2014!

Hover mouse over a date to see the map (dates are listed as two-digit month followed by two-digit date, so that 0501 indicates May 1st):

0110 0404 0428 0430 0506 0522 0523 0525 0527 0530 0602 0609 0615 0617 0618 0619 0620 0621 0624 0626 0629 0707 0717 0722 0806 0810 0812 0813 0815 0816 0817 0818 0820 0822 0823 0824 0827 0828
0829 0905 0909 0910 0912 0918 0919 0920 0921 0922 0923 0930 1001

Data sources and notes:
Gridded recurrence interval data were provided by The Automated Geospatial Watershed Assessment Tool website.
That is based on data in Hershfield, D. M., 1961: Rainfall frequency atlas of the United States. U.S. Weather Bureau Technical Paper 40, 115 pp.
Precipitation data is the Stage IV analysis over the US, obtained in real-time from NOAA/NCEP.
Archived precipitation data come from NCAR/EOL.
The Stage IV analysis data have been coarsened slightly for this analysis, to a grid with approximately 8.25-km horizontal spacing. We have found that this helps to eliminate the identification of spurious events, although it may also remove legitimate events that occurred at very small spatial scales.
Currently, the analysis has only been conducted for states east of the Rockies, but we hope to extend it to the full US (using updated recurrence interval information where available) in the future.
Maps of events exceeding the 1-hour precipitation thresholds are not yet available, but we hope to post them soon.

Acknowledgments:
Stephanie Stevenson (undergraduate researcher at Texas A&M University) created the archived images (for the years 2002--2010) and performed most of the data analysis.
This work was published in Stevenson and Schumacher (2014, Monthly Weather Review). Please cite this paper if you make use of the data or analyses from this website in your own research.
This material is based upon work supported by the National Science Foundation under Grant Nos. AGS-0954908 and AGS-1157425. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.