Big Horn County, Montana
County storm and disaster record · FIPS 30003 · population 13,034 · 4,998 sq mi
NOAA's Storm Events Database holds 787 records for Big Horn County, Montana from 1950 through June 30, 2026, on 455 days; the most frequent are hail reports (248 records). The deadliest single record is the July 16, 2008 thunderstorm wind: 2 deaths. FEMA has issued 9 declarations naming the county since 1978, 7 of them for natural hazards; the latest for a natural hazard was “Severe Winter Storm and Straight-Line Winds” on April 7, 2026.
The record, 1950 to 2026
Storm records filed for the county each year (2026 to June 30, 2026). Before 1996 NOAA recorded only tornadoes (from 1950), thunderstorm wind and hail (from 1955).
- recorded, no damage figure
- under $100,000
- $100,000 or more
- $1 million or more
- $10 million or more, or a death
- $100 million or more, or 10 deaths
- a year's colour: its recorded damage or deaths
- a year with a death
- 1955: wind and hail recorded from 1955
- 1996: all 48 event types from 1996
- Storm records
- 787on 455 days, 1950 to June 30, 2026
- Deaths recorded
- 921 injuries
- Damage, 2025 dollars
- $8.8Mas filed (scale steps before 1993)
- Tornadoes
- 10strongest EF1
- FEMA declarations
- 9latest 2026
Source: NOAA NCEI Storm Events Database, records through June 30, 2026 (file revision 20260918); damage converted to 2025 dollars with the BLS CPI-U. Search the record at NCEI. BLS consumer price index.
What hazards hit Big Horn County most?
The most frequent records are hail reports: 248 since 1956. 79% of its hail reports since 1956 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.
| Hazard | Records | Days | First, last | Killed | Injured | Damage | Rank in state |
|---|---|---|---|---|---|---|---|
| Hail | 248 | 142 | 1956-2026 | 0 | 0 | $211K | 32 of 56 |
| Winter storms | 219 | 141 | 1998-2026 | 2 | 3 | $2.0M | 45 of 56 |
| Severe thunderstorm wind | 155 | 93 | 1970-2026 | 4 | 18 | $38K | 38 of 56 |
| High wind and dust storms | 101 | 81 | 1998-2026 | 0 | 0 | – | 51 of 56 |
| Floods | 25 | 20 | 1997-2023 | 1 | 0 | $5.2M | 43 of 56 |
| Wildfires | 11 | 10 | 2001-2024 | 0 | 0 | – | 24 of 56 |
| Tornadoes | 10 | 9 | 1965-2018 | 0 | 0 | $1.3M | 29 of 56 |
| Heavy rain | 5 | 3 | 2005-2007 | 0 | 0 | – | 51 of 56 |
| Drought | 4 | 1 | 2021-2021 | 0 | 0 | – | 26 of 56 |
| Extreme cold | 4 | 2 | 1998-2000 | 0 | 0 | – | 50 of 56 |
| Fog, smoke and funnel clouds | 3 | 3 | 2001-2010 | 0 | 0 | – | 46 of 56 |
| Heat | 1 | 1 | 2011-2011 | 1 | 0 | – | 23 of 56 |
| Lightning | 1 | 1 | 1999-1999 | 1 | 0 | – | 25 of 56 |
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 Big Horn County had?
NOAA records 10 tornadoes in Big Horn County from 1965 to 2018, the strongest rated EF1, with 0 deaths and 0 injuries 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 11 tornadoes whose track touched Big Horn County since 1950 (NOAA's county records number 10: they file a crossing tornado once per county segment, and the two databases differ on some tracks); along their whole tracks they killed 0 people.
Map of the strongest tornado tracks in Montana.
Every tornado record filed for Big Horn County (10)
| Date | Place | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2018-06-07 | Kirby, Big Horn County | EF1 0.75 mi x 100 yd | 0 | 0 | – |
| 1996-06-22 | Hardin, Big Horn County | F1 4 mi x 5 yd | 0 | 0 | – |
| 1996-05-13 | Kirby, Big Horn County | F0 0.1 mi x 5 yd | 0 | 0 | – |
| 1991-07-09 | Big Horn County | F1 0.1 mi x 10 yd | 0 | 0 | $25K step |
| 1991-06-21 | Big Horn County | F1 0.2 mi x 10 yd | 0 | 0 | $250K step |
| 1984-06-21 | Big Horn County | F1 1 mi x 50 yd | 0 | 0 | – |
| 1984-06-21 | Big Horn County | F1 2 mi x 50 yd | 0 | 0 | $250K step |
| 1978-06-24 | Big Horn County | 0 | 0 | – | |
| 1968-06-13 | Big Horn County | F0 | 0 | 0 | $250 step |
| 1965-07-12 | Big Horn County | 0 | 0 | – |
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, 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 Big Horn County?
The most recent record with damage, injuries or deaths is the July 15, 2022 thunderstorm wind (1 death and 14 injuries).
Around 4:15 PM MDT, a thunderstorm outflow moved through the Hardin area. It produced a wind gust of 62 mph in the 4:35 PM MDT observations from the Big Horn County Airport. Along with the outflow winds, blowing dust reduced visibility to less than a quarter mile on the AWOS. This resulted in a 20 to 30 vehicle pile up along Interstate 90 around mile marker 493 reported at 4:30 PM MDT, very close to the airport. Prior to this, the Montana DOT RWIS station at Arrow Creek Hill, 25 miles west of Hardin, reported a peak wind gust of 48 mph about 15 minutes prior. This accident resulted in 6 deaths and multiple injuries.
National Weather Service event narrative, NOAA Storm Events Database (search the full record, event 1038034)
| Date | Record | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2026-06-27 | HailCrow Agency, Big Horn County | 1.00 in hail | 0 | 0 | – |
| 2026-06-22 | Thunderstorm WindLodge Grass, Big Horn County | 62 kt wind | 0 | 0 | – |
| 2026-05-13 | Thunderstorm WindLodge Grass, Big Horn County | 70 kt wind | 0 | 0 | – |
| 2026-05-13 | Thunderstorm WindKirby, Big Horn County | 56 kt wind | 0 | 0 | – |
| 2026-05-13 | Thunderstorm WindHardin, Big Horn County | 51 kt wind | 0 | 0 | – |
| 2026-04-02 | Winter StormBig Horn County and Carbon County · forecast zone Pryor/Northern Bighorn Mountains | 0 | 0 | – | |
| 2026-04-02 | Winter StormBig Horn County and Carbon County · forecast zone Bighorn Canyon | 0 | 0 | – | |
| 2026-04-02 | Winter StormBig Horn County · forecast zone Southern Big Horn | 0 | 0 | – | |
| 2026-04-02 | Winter StormBig Horn County · forecast zone Northern Big Horn | 0 | 0 | – | |
| 2026-03-12 | Winter StormBig Horn County · forecast zone Southern Big Horn | 0 | 0 | – | |
| 2026-03-12 | Winter StormBig Horn County · forecast zone Northern Big Horn | 0 | 0 | – | |
| 2026-03-12 | High WindBig Horn County and Carbon County · forecast zone Pryor/Northern Bighorn Mountains | 63 kt wind | 0 | 0 | – |
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
| Date | Record | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2008-07-16 | Thunderstorm WindDecker, Big Horn County Two fatalities, both drownings, occurred from a severe thunderstorm that moved across the Tongue River Reservoir. A man fell from a dock and a woman drowned when her small boat capsized as a result of very strong thunderstorm winds. | 61 kt wind | 2 | 0 | – |
| 2022-07-15 | Thunderstorm WindHardin, Big Horn County Around 4:15 PM MDT, a thunderstorm outflow moved through the Hardin area. It produced a wind gust of 62 mph in the 4:35 PM MDT observations from the Big Horn County Airport. Along with the outflow winds, blowing dust reduced visibility to less than a quarter mile on the AWOS. This resulted in a 20 to 30 vehicle pile ... | 56 kt wind | 1 | 14 | – |
| 2021-12-27 | Winter WeatherBig Horn County · forecast zone Northern Big Horn A motor vehicle crash on River Crow Road north of Crow Agency resulted in 1 fatality. | 1 | 2 | – | |
| 2009-02-19 | Winter WeatherBig Horn County · forecast zone Southern Big Horn As a result of the icy roads, a 16 year old girl died in a one-vehicle crash on Interstate 90 near Dunmore, Montana. Although I-90 was icy and snowpacked at the time, Montana Highway Patrol said speed was a factor. | 1 | 1 | – | |
| 2021-08-16 | Thunderstorm WindCrow Agency, Big Horn County A strong thunderstorm outflow passed over Crow Agency around 630pm with winds to 55 mph. A couple hours later, a shower with up to 20dbz moved over Crow Agency around 830pm, producing winds to 64 mph across a small area. A roof blew off an arbor, throwing it across the street, striking a camper in the head and throat. | 56 kt wind | 1 | 0 | – |
| 2011-08-17 | HeatBig Horn County · forecast zone Northern Big Horn Big Horn County Coroner reported that a 3-year-old boy died after being left in a parked car for several hours in Hardin. The boy died during the late afternoon hours when temperatures were in the lower 90s. | 1 | 0 | – | |
| 2011-05-24 | Flash FloodSt Xavier, Big Horn County Water was reported to be flowing over Highway 313 near Soap Creek. Heavy rainfall impacted streams draining into the St Xavier area. In addition, a body was found in a flooded vehicle at the Koyamas Pond recreation area near the Big Horn River. | 1 | 0 | – | |
| 1999-07-17 | LightningDecker, Big Horn County A 13 year old girl was stuck and killed by lightning on the Tongue River Reservoir. | 1 | 0 | – |
| Date | Record | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2011-05-21 | FloodBig Horn Wye, Big Horn County | 0 | 0 | $5.2M | |
| 2001-04-09 | Heavy SnowBig Horn County · forecast zone Big Horn | 0 | 0 | $2.0M | |
| 1998-07-05 | HailHardin, Big Horn County | 2.75 in hail | 0 | 0 | $181K |
Before 1993 NOAA filed damage by category, not amount, so the list above starts in 1993. The highest category filed here before then (entered as $250K, in the dollars of the day) holds: June 21, 1984 (tornado, Big Horn County); June 21, 1991 (tornado, Big Horn County).
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 Big Horn 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).
| Hazard | 1950s | 1960s | 1970s | 1980s | 1990s | 2000s | 2010s | 2020-26 |
|---|---|---|---|---|---|---|---|---|
| Hail | 8 | 9 | 1 | 2 | 38 | 96 | 67 | 27 |
| Winter storms | – | – | – | – | 3 | 64 | 63 | 89 |
| Severe thunderstorm wind | 0 | 0 | 2 | 2 | 18 | 52 | 48 | 33 |
| High wind and dust storms | – | – | – | – | 7 | 17 | 27 | 50 |
| Floods | – | – | – | – | 1 | 9 | 14 | 1 |
| Wildfires | – | – | – | – | 0 | 2 | 6 | 3 |
Source: NOAA NCEI Storm Events Database, records per calendar decade; zone records from the CZ_TYPE field (Z).
What time of year?
79% of its hail reports since 1956 fell in June and July. The two busiest months are in violet.
The values, month by month
Jan 44 · Feb 57 · Mar 54 · Apr 47 · May 62 · Jun 186 · Jul 157 · Aug 60 · Sep 11 · Oct 31 · Nov 36 · Dec 42 (records).
Source: NOAA NCEI Storm Events Database, records by the month they began.
Federal disaster declarations for Big Horn County
FEMA's register lists 9 declarations that include Big Horn County: 6 major disasters, 2 emergencies and one fire management assistance declaration. Most were for fire (2) and biological (2).
| Declared | Number | Type | Title |
|---|---|---|---|
| 2026-04-07 | DR-4902 | Straight-Line Winds | Severe Winter Storm and Straight-Line Winds |
| 2021-07-28 | FM-5403 | Fire | Pf Fire |
| 2020-03-31 | DR-4508 | Biological | Covid-19 Pandemic |
| 2020-03-13 | EM-3476 | Biological | Covid-19 |
| 2011-06-17 | DR-1996 | Severe Storm | Severe Storms and Flooding |
| 2005-09-13 | EM-3253 | Hurricane | Hurricane Katrina Evacuation |
| 2001-05-28 | DR-1377 | Severe Storm | Severe Winter Storms |
| 2000-08-30 | DR-1340 | Fire | Wildfires |
| 1978-05-29 | DR-558 | Flood | Severe Storms & Flooding |
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 Big Horn County had?
NOAA's Storm Events Database holds 25 flood or flash flood records for Big Horn County from 1997 to 2023, on 20 days, with 1 death. By flood insurance claims since 1978 (OpenFEMA, as of September 8, 2026), Big Horn County ranks 2181st of 2,942 U.S. counties.
The National Flood Insurance Program has paid $245,000 on 16 claims filed in Big Horn County; the most in one year was 7 in 1978. Claims count insured losses only: uninsured flood damage is not in this file.
The values, year by year
1978: 7 · 1979: 2 · 1995: 1 · 2001: 1 · 2011: 5; the other years: 0.
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 Big Horn County
FEMA's National Risk Index rates Big Horn County Relatively Low overall, with an expected annual loss of $11.2 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.
| Hazard | Risk rating | Expected annual loss | Modeled frequency |
|---|---|---|---|
| Strong Wind | Relatively High | $1.9M | about once a year (modeled) |
| Winter Weather | Relatively High | $212K | 24 a year (modeled) |
| Lightning | Relatively High | $493K | 32 a year (modeled) |
| Wildfire | Relatively Moderate | $2.0M | once in about 162 years (modeled) |
| Cold Wave | Relatively Moderate | $1.8M | 3.1 a year (modeled) |
| Landslide | Relatively Low | $5K | 5.2 a year (modeled) |
| Riverine Flooding | Relatively Low | $4.5M | about once a year (modeled) |
| Hail | Relatively Low | $164K | 1.6 a year (modeled) |
Source: FEMA National Risk Index, county table, December 2025 release. FEMA's National Risk Index map.
Counties that share a border with Big Horn County
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 Big Horn CountyThe hazard risk calculator: 18 hazards beside the county's record
- Download Big Horn County's FEMA declarations (CSV)9 rows: every declaration that named the county, for your own analysis