Rock County, Minnesota

What hazards hit Rock County most?

The most frequent records are winter storm records: 196 since 1996. 43% of its winter storm records since 1996 fell in December and January. The rank column places the county among Minnesota'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 Rock County had?

NOAA records 15 tornadoes in Rock County from 1956 to 2026, the strongest rated F2, with 0 deaths and 7 injuries recorded in the county. That is 37th of 87 Minnesota 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 15 tornadoes whose track touched Rock County since 1950 (NOAA's county records number 15, the same count); along their whole tracks they killed 0 people.

Map of the strongest tornado tracks in Minnesota.

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 Rock County?

The most recent record with damage, injuries or deaths is the June 21, 2024 flood ($1.9 million in damage in 2025 dollars).

Rainfall amounts across Rock County from June 20-22 ranged from 2 to 7 inches. Widespread overland flooding ensued with additional moderate to major flooding along the Rock River and Split Rock Creek. During peak flooding, numerous township, county, and state roads were under water and closed. A No Travel Advisory was issued by law enforcement. Interstate 90 was under water and briefly closed between Luverne and Worthington where a swift water rescue was conducted near mile marker 17. U.S. Highway 75 was also closed from Luverne to the Iowa state line. In Luverne, numerous roads were reported under water and flood waters from the Rock River inundated Redbird Field and the Luverne City Park. Preliminary damage assessments estimate loss to public infrastructure to be at least 2 million dollars.
National Weather Service event narrative, NOAA Storm Events Database (search the full record, event 1196743)

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

A damage figure marked "step" is a record from before 1993: NOAA then filed damage by category, and the figure is the category as entered, in the dollars of that year, not an estimate of the loss.

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 Rock 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).

High wind and dust storms in the 2020-26: 25 records against 7 in the decade before, 25 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 Rock 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?

43% of its winter storm records since 1996 fell in December and January. The two busiest months are in violet.

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

Federal disaster declarations for Rock County

FEMA's register lists 16 declarations that include Rock County: 13 major disasters, 3 emergencies and 0 fire management assistance declarations. Most were for flood (6) and severe storm (6).

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 Rock County had?

NOAA's Storm Events Database holds 68 flood or flash flood records for Rock County from 1997 to 2024, on 48 days, with 0 deaths. By flood insurance claims since 1978 (OpenFEMA, as of September 8, 2026), Rock County ranks 1928th of 2,942 U.S. counties.

The National Flood Insurance Program has paid $162,000 on 29 claims filed in Rock County; the most in one year was 9 in 2014. 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 Rock County

FEMA's National Risk Index rates Rock County Very Low overall, with an expected annual loss of $6.6 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 Rock County

1. Minnehaha County, SD 1,554
2. Nobles County 812
3. Lyon County, IA 774
4. Rock County 701
5. Pipestone County 673
6. Moody County, SD 657
7. Murray County 639

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 MinnesotaEvery Minnesota tornado since 1950 and the counties with the most per square mile
• Winter storms in MinnesotaThe state's winter storm records, by county, year and month
• The Minnesota recordEvery hazard in the state, its deadliest events and its federal declarations
• FEMA's risk rating for each hazard in Rock CountyThe hazard risk calculator: 18 hazards beside the county's record
• Download Rock County's FEMA declarations (CSV)16 rows: every declaration that named the county, for your own analysis