Sioux County, Nebraska

What hazards hit Sioux County most?

The most frequent records are hail reports: 243 since 1955. 67% of its hail reports since 1955 fell in June and July. The rank column places the county among Nebraska'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 Sioux County had?

NOAA records 29 tornadoes in Sioux County from 1951 to 2021, the strongest rated EF2, with 0 deaths and 1 injury recorded in the county. 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 29 tornadoes whose track touched Sioux County since 1950 (NOAA's county records number 29, the same count); along their whole tracks they killed 0 people.

Map of the strongest tornado tracks in Nebraska.

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 Sioux County?

The most recent record with damage, injuries or deaths is the June 12, 2017 tornado (1 injury and $7,224 in damage in 2025 dollars).

A tornado crossed the WY/NE state line into Sioux County, NE at 1630 MST, and continued northeast before lifting west of Highway 29, 8 miles south-southwest of Harrison, NE at 1701 MST. Damage consistent with EF-2 intensity was noted by the survey team to the residence, as well as to surrounding trees and outbuildings (DI 2, DOD 6) 13 miles southwest of Harrison, NE. One resident at this location was treated and released at a local hospital with injuries incurred from flying debris in the home.
National Weather Service event narrative, NOAA Storm Events Database (search the full record, event 721662)

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 Sioux 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).

Winter storms in the 2010s: 101 records against 18 in the decade before, 101 of them forecast-zone records. High wind and dust storms in the 2010s: 30 records against 6 in the decade before, 30 of them forecast-zone records. Cells marked z rose mostly through zone records. The local National Weather Service office files these once per forecast zone, so a change in how it draws its zones or splits a storm into records moves this count as much as the weather does; read it beside the Sioux County days with a record above.

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

What time of year?

67% of its hail reports since 1955 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 Sioux County

FEMA's register lists 14 declarations that include Sioux County: 9 major disasters, 2 emergencies and 3 fire management assistance declarations. Most were for severe storm (6) and fire (3).

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.

FEMA's modeled risk for Sioux County

FEMA's National Risk Index rates Sioux County Very Low overall, with an expected annual loss of $1.9 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 Sioux County

1. Scotts Bluff County 1,105
2. Fall River County, SD 1,001
3. Goshen County, WY 959
4. Dawes County 772
5. Box Butte County 723
6. Sioux County 594
7. Niobrara County, WY 489

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 NebraskaEvery Nebraska tornado since 1950 and the counties with the most per square mile
• Hail in NebraskaThe state's hail reports, by county, year and month
• The Nebraska recordEvery hazard in the state, its deadliest events and its federal declarations
• FEMA's risk rating for each hazard in Sioux CountyThe hazard risk calculator: 18 hazards beside the county's record
• Download Sioux County's FEMA declarations (CSV)14 rows: every declaration that named the county, for your own analysis