harshithkethavath/FloodPrint-LSR-WS2024

FloodPrint: NWS Flash Flood Local Storm Reports (Warm Season 2024)

Part of the FloodPrint Collection — a CONUS-scale dataset for NWS Flash Flood Warning verification research.

Dataset Summary

This dataset contains quality-controlled Flash Flood Local Storm Reports (LSRs) for the contiguous United States (CONUS) covering the 2024 warm season (April–September 2024). LSRs are point observations collected by NWS Weather Forecast Offices (WFOs) from storm spotters, emergency managers, public reports, and automated sensors.

This dataset is the Phase 1 output of the FloodPrint pipeline and serves as the observational ground truth for flash flood warning verification.

Dataset Details

Property	Value
Record count	~4,730
Geographic coverage	CONUS
Temporal coverage	April 1 – September 30, 2024
Temporal resolution	Per-event (UTC timestamp)
Spatial representation	Point observations (lat/lon)
Source	Iowa Environmental Mesonet (IEM) API
File format	Parquet

Data Fields

Column	Type	Description
valid_utc	datetime64[UTC]	Timestamp of the LSR observation (UTC)
lat	float64	Latitude of the reported event (decimal degrees)
lon	float64	Longitude of the reported event (decimal degrees)
magnitude	float64	Reported magnitude where applicable (e.g. rainfall depth in inches); NaN if not reported
remark	str	Free-text remark from the reporting spotter or agency
wfo	str	3-letter NWS Weather Forecast Office identifier that collected the report (e.g. GSP, LWX)

Data Collection and Quality Control

LSRs were fetched from the IEM GeoJSON API endpoint. The following quality control steps were applied:

• Type filter: Only FLASH FLOOD type LSRs retained; all other hazard types excluded
• Coordinate validation: LSRs with coordinates outside the CONUS bounding box removed
• Duplicate removal: LSRs within 1 km and 30 minutes of each other collapsed to a single record (duplicate reporting artifact common in high-profile events)
• Raw vs. clean: The raw pre-QC fetch is not distributed; only this cleaned version is released

Known Limitations

Spotter density bias: LSRs are not comprehensive event coverage. In sparsely populated or rural regions, flash floods may occur without generating any LSR because there are no nearby spotters or because the event went unreported. This bias is most pronounced in the desert Southwest and sparsely populated rural areas of the Great Plains. Any downstream analysis using this dataset should account for this explicitly (e.g., restricting to counties above the 25th percentile of historical LSR density, or including population density as a covariate).

Source

All LSRs sourced from the Iowa Environmental Mesonet (IEM):

https://mesonet.agron.iastate.edu/cgi-bin/request/gis/lsr.py

IEM data is freely and publicly available. This dataset redistributes a cleaned and filtered subset.

Citation

If you use this dataset, please cite the FloodPrint project and the IEM data source:

@dataset{floodprint_lsr_ws2024,
  author    = {Kethavath, Harshith},
  title     = {FloodPrint: NWS Flash Flood Local Storm Reports (Warm Season 2024)},
  year      = {2026},
  publisher = {HuggingFace},
  url       = {https://huggingface.co/datasets/harshithkethavath/FloodPrint-LSR-WS2024}
}

Original data source: Iowa Environmental Mesonet (IEM), Iowa State University. https://mesonet.agron.iastate.edu

License

Creative Commons Attribution 4.0 International (CC BY 4.0) — source data is publicly available from NOAA/IEM with no use restrictions.