Storm Events database
Hail and wind · Cloudbreak team · Updated October 29, 2026 · 9 sources
Definition
The Storm Events Database is the public, searchable archive of NWS Storm Data kept by NOAA's National Centers for Environmental Information (NCEI). It records US storms intense enough to cause deaths, injuries, significant property damage or disruption to commerce, plus rare or unusual weather, from January 1950 on.1,2
How it works
Each entry is a report that a hazard, such as hail, damaging wind or a tornado, struck a county or forecast zone at a given time, with what was measured and what was damaged. The database is a record of storms that were reported and certified, not a complete map of every storm.
NWS offices gather reports from emergency managers, law enforcement, SKYWARN spotters, NWS damage surveys, newspaper clipping services, the insurance industry and the public. Each forecast office has 60 days after month end to certify its data; NCEI gets the national file at about 75 days and updates the database within 75 to 90 days.2,3
An episode is a whole storm system; an event is one hazard type in one county or zone, such as a hail report or a tornado segment. Tornado, thunderstorm wind, hail and flash flood events are usually logged by county; heat, cold, drought and winter storms by NWS forecast zone.2,4
What a record holds
Each event has a start and end time, location, magnitude, deaths, injuries, property and crop damage, the report source and a narrative. Hail is sized in hundredths of an inch and wind in knots, marked measured gust (MG), measured sustained (MS), estimated gust (EG) or estimated sustained (ES).2,3,4
Records for 1950 to 1992 came mostly from SPC files holding only tornadoes (from 1950) and thunderstorm wind and hail (from 1955). Zone-based events from 1993 to 1995 were left out.5
Example
On April 28, 2021, storms hit northern Tarrant County, Texas, hardest, with hail up to 3.25 inches across. The episode narrative estimates hail damage at over $500 million, with roofs, windows and cars damaged or shattered. Five of its 42 event records:4
| Time (as recorded, CST-6) | Location (as recorded) | Hail size | Property damage |
|---|---|---|---|
| 7:14 p.m. | FT WORTH SAGINAW ARP | 1.75 in. | $18.00M |
| 7:15 p.m. | FT WORTH SAGINAW ARP | 3.00 in. | $40.00M |
| 7:20 p.m. | BLUE MOUND | 2.00 in. | $18.00M |
| 7:30 p.m. | KELLER | 2.50 in. | $40.00M |
| 7:37 p.m. | 1.5NNW KELLER ALTA VISTA AR | 2.50 in. | $40.00M |
The 7:37 p.m. record's source is an NWS employee, and its narrative reads in full: "Tennis ball size hail was reported by an NWS Employee." Many records carry the same $18.00M or $40.00M amount, and NWS rules round damage entries to three significant digits.4,3,2
Known limits
The database is strongest as a record that a storm happened, roughly when and where. It is weaker on how large the hail was, how far it reached and what it cost.
- Damage is entered as actual dollars when an insurer or other qualified source has a reasonably accurate estimate; otherwise the preparer estimates it or checks "no information available," except for floods, which always get an amount. Amounts are not adjusted for inflation.3,2
- A tropical cyclone event counts wind damage only; surge, rain flooding and tornadoes from the storm are separate event types.2
- NWS may not verify outside reports; NCEI's disclaimer urges caution with them.2
- Hail sizes cluster at common objects.6
- Severe hail reports in SPC's database rose from under 350 in 1955 to over 12,500 in 2002, likely from changes in society and NWS reporting more than in hail climatology, SPC authors say.6
- A field study of 73 severe hailstorms from 2011 to 2015 found Storm Data averaged 3 hail reports per storm against 66 field measurements, 32% of storms had none in Storm Data, and recorded sizes often understated the largest hail.7
- Thunderstorm wind and hail from 1959 to 1995 are usually a single point accurate to about 1 mile. Since October 2006, coordinates are entered to four decimal places.2
Where you'll see it
- The NCEI search pages, by map, address, county or keyword, with CSV downloads and bulk files in a public Google Cloud Storage bucket.1,2,8
- Custom PDF reports from a search; NCEI certifies a report on request to ncei.orders@noaa.gov.1
- The monthly Storm Data publication, the official NOAA record the database is built from.1,2
- SPC's preliminary Storm Reports page, which points to the database for official, final severe weather data.9
Questions
- How far back does the NOAA Storm Events Database go?
- To January 1950, but records from 1950 to 1992 hold only tornadoes and, from 1955, thunderstorm wind and hail. Zone-based events such as winter storms are missing for 1993 to 1995.1,5
- How long does it take for a storm to appear in the Storm Events Database?
- About 75 to 90 days after the month ends; January data usually reach NCEI around April 15. SPC's preliminary Storm Reports page lists NWS local storm reports sooner, but is incomplete.2,9
- How accurate are Storm Events Database damage estimates?
- They are broad estimates, made with the data available when the event was entered and not adjusted for inflation. Where an insurer or other qualified source has a reasonably accurate figure, that is used.2,3
- Why isn't a storm in the Storm Events Database?
- Only weather rare or intense enough to cause deaths, injuries, significant property damage or disruption to commerce is recorded, and only if someone reported it. NCEI asks people to report missing events to their local NWS office.2
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Sources
Written by the Cloudbreak team. Numbers, dates and rules cite the published sources below.
- 1. NOAA National Centers for Environmental Information: Storm Events Database
- 2. NOAA National Centers for Environmental Information: Storm Events Database FAQ
- 3. NOAA National Weather Service: NWS Instruction 10-1605: Storm Data Preparation (July 26, 2021)
- 4. NOAA National Centers for Environmental Information: Storm Events Database, Event 956694: Hail, Tarrant County, Texas, April 28, 2021
- 5. NOAA National Centers for Environmental Information: About the Storm Events Database
- 6. NOAA Storm Prediction Center: The Frequency of Large Hail over the Contiguous United States (Schaefer, Levit, Weiss and McCarthy)
- 7. American Meteorological Society, via NOAA Central Library: High-Resolution Hail Observations: Implications for NWS Warning Operations (Blair and others, Weather and Forecasting, 2017)
- 8. NOAA National Centers for Environmental Information: Storm Events Database User Guide
- 9. NOAA Storm Prediction Center: SPC Frequently Asked Questions