Extreme Precipitation Event Catalog (EPEC)

*** UPDATED 2026-07-13 *** The EPEC is a catalogue of labelled extreme precipitation events resolved at 0.03332 degrees (~4km) hourly across the Contiguous United States (CONUS) from January 2002 through December 2025. This event-based approach offers novel insights into the space and time evolving structure of extreme precipitation, enabling understanding of extreme precipitation event characteristics and trends at local scales. EPEC includes 27,425 storms labelled as microscale (n = 6,429), mesoscale (n = 19,839), synoptic (n = 1,025), and Tropical Cyclone (n = 132). The intended audience includes flood hazard research scientists interested in modeling hydrologic and hydraulic response from extreme precipitation events, civil engineers, city managers, and watershed planners interested in understanding recent trends in extreme precipitation events at scales relevant to planning design, and private industry including banking, insurance, and reinsurance organizations interested in reducing portfolio-scale risks. EPEC is created by combining NOAA Analysis of Record for Calibration (AORC), NOAA Atlas 14 Annual Recurrence Intervals (ARIs), unsupervised clustering using Density-Based Spatial Clustering of Applications with Noise (DBSCAN), and supervised classification using Random Forest (RF). Each event within the EPEC includes two GeoTIFF files, a PNG file, and a shapefile layer within the provided GeoPackage. Under the folder structure GeoTIFF -> intensity and GeoTIFF -> return_period, each GeoTIFF file is named using the convention 'YYYY-MM-DD-XXX.tif' where YYYY-MM-DD is the year-month-day associated with the first day of the precipitation event and XXX is the storm ID number within that day. Within the intensity folder, GeoTIFF layers are named using the convention 'tYYYYMMDD_HHMMSS' which represents the date time for each time step. Raster values represent hourly precipitation derived from NOAA AORC and are in units of millimeters per hour (mm/hr). A csv file is included (cluster_characteristics_from_intensity_tifs_labelled_predict_latest.csv) which describes individual event characteristics and the probability of each event's classification as one of four storm types (microscale, mesoscale, synoptic, and tropical cyclone). Storm types were determined using a Random Forest classification model trained (80%) and tested (20%) using a 10-fold cross-validation on a 10% sample of hand-labelled events from the catalogue. Hand-labeled events are defined under the 'label' column and all event predictions are defined under the 'predicted_class' column. Within the return period folder, single-layer GeoTIFFs compress storms lasting multiple hours into a single static summary of the event. Raster values represent maximum exceeded return period derived from NOAA Atlas 14 and are in units of years. While 27,522 rasters are included in each folder, we remove 97 events whose peak intensity exceeds 350 mm/hr for the associated manuscript. These events occur exclusively in the years 2024 and 2025. The dataset prior to the 2026-07-13 update is available within the archive folder.