Flash Flood Episodes - RUNOFF general modeling access

Flash flood episodes i

Browse every weather-caused flash flood episode in the lower 48, pick episodes by rainfall, return period and impact criteria, and download their events, Local Storm Reports and precomputed MRMS tables per watershed. No stream gage required, nothing to run: every number on this page was computed once from the MRMS archive.

The episode catalog has not been built in this copy of the site.
Build it from the repository root (Python 3.10+, pandas):
python engine/lsr/fetch_lsrs.py --wy 2021 2025
python engine/episodes/build_catalog.py --stormevents data/stormevents
then the MRMS statistics with engine/episodes/precompute_mrms.py and build_mrms_payload.py. See engine/episodes/README.md.

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States (none picked = all CONUS) Clear state selection Min flash flood events 0 i Min Local Storm Reports 0 i Min fatalities 0 Min reported damage $0 Min USGS gages in the footprint 0 i Sort episodes by

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Weather-caused flash floods only; dam and levee failure reports are excluded. Event locations are NWS report coordinates, not storm centers; the watershed footprint and the MRMS fields describe the storm itself. Sources: NOAA NCEI Storm Events Database; NWS Local Storm Reports and the MRMS archive via the Iowa Environmental Mesonet (NOAA MRMS on AWS as fallback); USGS Watershed Boundary Dataset; FLASH QPE ARI from NSSL.

Want all of it at once? The complete dataset behind this page, one folder of flat tables with a data dictionary and a worked notebook, is in the repository: storm_episodes on GitHub.

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episode (matches filters)

Storm Events flash flood

Local Storm Report

USGS gage (under 1000 km2)