Nelson County, North Dakota

What hazards hit Nelson County most?

The most frequent records are hail reports: 187 since 1971. 69% of its hail reports since 1971 fell in June and July. The rank column places the county among North Dakota's counties by days with a record per 1,000 square miles of land over each hazard's complete period.

Source: NOAA NCEI Storm Events Database (county and forecast-zone records attributed to the county; a zone record shows its own totals on each county it covers). Days: dates with at least one record of the hazard in the county. Ranks: days with a record per 1,000 square miles of land (Census Bureau 2024 Gazetteer), since 1950 for tornadoes, 1955 for hail and thunderstorm wind, 1996 for the rest.

How many tornadoes has Nelson County had?

NOAA records 41 tornadoes in Nelson County from 1976 to 2022, the strongest rated EF3, with 0 deaths and 0 injuries recorded in the county. That is 9th of 53 North Dakota counties by days with tornadoes per 1,000 square miles since 1950. A tornado that crossed a county line is counted in each county it touched, with the length of its path inside the county.

Counted as whole tornadoes rather than county records, the Storm Prediction Center's database holds 41 tornadoes whose track touched Nelson County since 1950 (NOAA's county records number 41, the same count); along their whole tracks they killed 0 people.

Map of the strongest tornado tracks in North Dakota.

Source: NOAA NCEI Storm Events Database, tornado records by county (path length in the county, maximum width); ratings as published: F scale before February 1, 2007, EF scale after. Whole-track figures: NOAA Storm Prediction Center tornado database (1950-2025). SPC severe weather database.

When was the last damaging storm in Nelson County?

The most recent record with damage, injuries or deaths is the September 21, 2019 flash flood ($5.9 million in damage in 2025 dollars).

Streets, low spots, rivers, and basements were flooded by 4 to 9 inches of rain over a short duration of time. Cars that got stuck in the flood waters were abandoned where they stalled. Farm fields and access roads were also flooded.
National Weather Service event narrative, NOAA Storm Events Database (search the full record, event 855446)

Source: NOAA NCEI Storm Events Database; every record of 2025-2026 is listed, earlier ones when they caused deaths, injuries or $250,000 of damage (2025 dollars), and every tornado.

The deadliest and costliest records

Source: NOAA NCEI Storm Events Database: deaths and injuries direct and indirect; damage is property plus crops as estimated by the National Weather Service, converted to 2025 dollars.

Is it getting more frequent?

Records per decade for Nelson County's most frequent hazards. Counts rose everywhere after 1996, when NOAA began recording every event type, so compare decades within a hazard's complete period only (the shaded cells come before it).

Source: NOAA NCEI Storm Events Database, records per calendar decade; zone records from the CZ_TYPE field (Z).

What time of year?

69% of its hail reports since 1971 fell in June and July. The two busiest months are in violet.

Source: NOAA NCEI Storm Events Database, records by the month they began.

Federal disaster declarations for Nelson County

FEMA's register lists 33 declarations that include Nelson County: 29 major disasters, 4 emergencies and 0 fire management assistance declarations. Most were for flood (17) and severe storm (12).

Source: FEMA OpenFEMA Disaster Declarations Summaries (v2), declarations through October 2, 2026; one declaration is counted once however many areas it names. OpenFEMA dataset page.

How many floods has Nelson County had?

NOAA's Storm Events Database holds 59 flood or flash flood records for Nelson County from 1996 to 2019, on 56 days, with 0 deaths. By flood insurance claims since 1978 (OpenFEMA, as of September 8, 2026), Nelson County ranks 1648th of 2,942 U.S. counties.

The National Flood Insurance Program has paid $1.0 million on 52 claims filed in Nelson County; the most in one year was 15 in 2006. Claims count insured losses only: uninsured flood damage is not in this file.

Source: FEMA OpenFEMA NFIP Redacted Claims, as of September 8, 2026; claims by year of loss, payments in the dollars of the year paid. OpenFEMA dataset page.

FEMA's modeled risk for Nelson County

FEMA's National Risk Index rates Nelson County Very Low overall, with an expected annual loss of $3.0 million. These are FEMA's model estimates of future loss from 18 hazards, not a count of what happened; they can differ from the record above.

Source: FEMA National Risk Index, county table, December 2025 release. FEMA's National Risk Index map.

Counties that share a border with Nelson County

1. Grand Forks County 1,357
2. Walsh County 1,059
3. Benson County 853
4. Ramsey County 815
5. Nelson County 725
6. Steele County 648
7. Griggs County 620
8. Eddy County 550

Source: U.S. Census Bureau county adjacency file; NOAA NCEI Storm Events Database, records since 1950. The Census Bureau's adjacency file.

Next

• Tornadoes in North DakotaEvery North Dakota tornado since 1950 and the counties with the most per square mile
• Hail in North DakotaThe state's hail reports, by county, year and month
• The North Dakota recordEvery hazard in the state, its deadliest events and its federal declarations
• FEMA's risk rating for each hazard in Nelson CountyThe hazard risk calculator: 18 hazards beside the county's record
• Download Nelson County's FEMA declarations (CSV)33 rows: every declaration that named the county, for your own analysis