Sources

StormWorn uses only primary public sources. We do not use commercial risk scores or data licensed for non-commercial use only. Each place page lists the vintage of every dataset it draws on, and the methodology explains how each is joined.

Dataset	Publisher	Span	What we use it for	Terms
Severe weather database: tornadoes	NOAA Storm Prediction Center	1950–2025	Every tornado: date, rating, path, width, casualties, counties	U.S. Government work, public domain
Severe weather database: hail and thunderstorm wind	NOAA Storm Prediction Center	1955–2025	Every hail and damaging wind report: time, place, size or speed, measured or estimated; severe wind days and the hail and wind hub	U.S. Government work, public domain
HURDAT2 best-track data	NOAA National Hurricane Center	1851–2025	Tropical cyclone tracks, winds and status every six hours	Public domain
Storm Events Database	NOAA National Centers for Environmental Information	1950–2026	Hail, wind, flood, winter, heat, cold and other events; damage; narratives	Public domain
Monitoring Trends in Burn Severity	U.S. Geological Survey and U.S. Forest Service	1984–2026	Large wildfire perimeters and acres	Public domain
NFIP Redacted Claims, version 3	FEMA (OpenFEMA)	1978–present	Flood insurance claims and payments by ZIP code and year	OpenFEMA terms: attribution statement, no re-identification
Disaster Declarations Summaries	FEMA (OpenFEMA)	1953–present	Major disaster, emergency and fire management declarations by county	OpenFEMA terms
Global Historical Climatology Network Daily	NOAA National Centers for Environmental Information	Station records, some from the 1890s	Daily temperature, precipitation and snowfall; all-time records	Public domain
National Water Prediction Service river gauges	NOAA National Weather Service	Crests from the 1800s; retrieved 2026-10-30	Flood stages and the highest and recent crests at river gauges; a page for every gauge with a crest above flood stage	Public domain
High tide flooding counts	NOAA Center for Operational Oceanographic Products and Services	1920s–present at long-term gauges	Days of minor, moderate and major high tide flooding per year at tide gauges	Public domain
Global Historical Tsunami Database	NOAA NCEI and the World Data Service	1700s–present for the U.S.	Where tsunamis reached U.S. shores, how high, and deaths	Public domain
U.S. volcanoes and National Volcanic Threat Assessment	U.S. Geological Survey	2018 assessment	Volcano locations, elevations and threat categories	Public domain
Landslide Inventories across the United States, version 3.0	U.S. Geological Survey	Compiled 2025 from 56 inventories	Mapped landslides, their sources and recorded deaths	Public domain (USGS data release)
nClimDiv county drought index	NOAA National Centers for Environmental Information	1895–2026	Monthly Palmer Drought Severity Index for every lower-48 county	Public domain
Hazard Mapping System smoke analysis	NOAA NESDIS	2005–present (density from 2011)	Daily smoke plumes traced from satellite imagery	Public domain
ANSS Comprehensive Earthquake Catalog	U.S. Geological Survey	1900–present	Earthquakes of magnitude 2.5 or more: time, place, depth, magnitude	Public domain
Applied Climate Information System	NOAA Regional Climate Centers	—	Cross-checks of station extremes	Public service
Cartographic boundaries, Gazetteer, population estimates, centres of population	U.S. Census Bureau	2020–2025	County and city geography, land area, population	Public domain
Public forecast zone–county correlation	National Weather Service	Current	Placing zone-based storm events in counties	Public domain

Refresh schedule

Storm events, flood insurance claims and disaster declarations are refreshed monthly. Tornado, hurricane and wildfire datasets are refreshed once a year, after each agency publishes its final figures for the previous year. Weather station records are refreshed with each monthly build.

Required notice

This product uses the Federal Emergency Management Agency’s OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency’s website(s).

No federal agency endorses StormWorn.