Yellowstone County, Montana

What hazards hit Yellowstone County most?

The most frequent records are hail reports: 507 since 1955. 61% of its hail reports since 1955 fell in June and July. The rank column places the county among Montana'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 Yellowstone County had?

NOAA records 21 tornadoes in Yellowstone County from 1955 to 2016, the strongest rated EF2, with 0 deaths and 3 injuries recorded in the county. That is 4th of 56 Montana 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 21 tornadoes whose track touched Yellowstone County since 1950 (NOAA's county records number 21, the same count); along their whole tracks they killed 0 people.

Map of the strongest tornado tracks in Montana.

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 Yellowstone County?

The most recent record with damage, injuries or deaths is the June 2, 2023 flash flood ($1.5 million in damage in 2025 dollars).

Many roads on the west side of Billings were flooded and closed. Gable Road was particularly hit hard. Birely Drain and Big Ditch overflowed their banks washing out a portion of Gable Road. The cost to repair Gable Road will be about 600K. Total flood damage costs to the city will be around $1M.
National Weather Service event narrative, NOAA Storm Events Database (search the full record, event 1113257)

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 Yellowstone 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?

61% 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 Yellowstone County

FEMA's register lists 14 declarations that include Yellowstone County: 6 major disasters, 2 emergencies and 6 fire management assistance declarations. Most were for fire (7) and flood (2).

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 Yellowstone County had?

NOAA's Storm Events Database holds 41 flood or flash flood records for Yellowstone County from 1997 to 2025, on 33 days, with 1 death. By flood insurance claims since 1978 (OpenFEMA, as of September 8, 2026), Yellowstone County ranks 797th of 2,942 U.S. counties.

The National Flood Insurance Program has paid $2.3 million on 272 claims filed in Yellowstone County; the most in one year was 52 in 1978. 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 Yellowstone County

FEMA's National Risk Index rates Yellowstone County Relatively Moderate overall, with an expected annual loss of $60.1 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 Yellowstone County

1. Yellowstone County 1,197
2. Stillwater County 984
3. Rosebud County 832
4. Carbon County 803
5. Big Horn County 787
6. Musselshell County 494
7. Golden Valley County 386
8. Treasure County 232

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