Musselshell County, Montana
County storm and disaster record · FIPS 30065 · population 4,705 · 1,869 sq mi
NOAA's Storm Events Database holds 494 records for Musselshell County, Montana from 1950 through June 30, 2026, on 298 days; the most frequent are hail reports (230 records). The most damaging was the May 23, 2011 flood ($7.9 million in 2025 dollars). FEMA has issued 15 declarations naming the county since 1977, 13 of them for natural hazards; the latest for a natural hazard was “Flooding” on October 11, 2023.
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
- 494on 298 days, 1950 to June 30, 2026
- Deaths recorded
- 00 injuries
- Damage, 2025 dollars
- $8.3Mas filed (scale steps before 1993)
- Tornadoes
- 5strongest F2
- FEMA declarations
- 15latest 2023
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 Musselshell County most?
The most frequent records are hail reports: 230 since 1955. 78% 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.
| Hazard | Records | Days | First, last | Killed | Injured | Damage | Rank in state |
|---|---|---|---|---|---|---|---|
| Hail | 230 | 92 | 1955-2025 | 0 | 0 | – | 16 of 56 |
| Winter storms | 87 | 76 | 1996-2026 | 0 | 0 | – | 35 of 56 |
| High wind and dust storms | 74 | 73 | 1999-2026 | 0 | 0 | – | 25 of 56 |
| Severe thunderstorm wind | 45 | 36 | 1983-2024 | 0 | 0 | $25K | 37 of 56 |
| Floods | 35 | 26 | 1997-2025 | 0 | 0 | $8.2M | 7 of 56 |
| Fog, smoke and funnel clouds | 6 | 6 | 1999-2025 | 0 | 0 | – | 16 of 56 |
| Tornadoes | 5 | 5 | 1986-2013 | 0 | 0 | $51K | 21 of 56 |
| Wildfires | 5 | 5 | 2012-2020 | 0 | 0 | – | 16 of 56 |
| Heavy rain | 3 | 3 | 1998-2026 | 0 | 0 | – | 37 of 56 |
| Extreme cold | 2 | 2 | 1998-2000 | 0 | 0 | – | 44 of 56 |
| Drought | 1 | 1 | 2021-2021 | 0 | 0 | – | 19 of 56 |
| Landslides and avalanches | 1 | 1 | 2013-2013 | 0 | 0 | – | 24 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 Musselshell County had?
NOAA records 5 tornadoes in Musselshell County from 1986 to 2013, the strongest rated F2, with 0 deaths and 0 injuries recorded in the county. That is 21st 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 6 tornadoes whose track touched Musselshell County since 1950 (NOAA's county records number 5: 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 Musselshell County (5)
| Date | Place | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2013-07-08 | Melstone, Musselshell County | EF0 0.5 mi x 50 yd | 0 | 0 | – |
| 2004-08-26 | Klein, Musselshell County | F0 | 0 | 0 | – |
| 1999-05-20 | Roundup, Musselshell County | F0 0.2 mi x 30 yd | 0 | 0 | $44K |
| 1992-07-10 | Musselshell County | F0 0.1 mi x 10 yd | 0 | 0 | – |
| 1986-05-04 | Musselshell County | F2 0.1 mi x 10 yd | 0 | 0 | $3K step |
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 Musselshell County?
The most recent record with damage, injuries or deaths is the May 23, 2011 flood ($7.9 million in damage in 2025 dollars).
Persistent heavy rainfall combined with snowmelt in the mountains resulted in extensive and significant flooding along the Musselshell River and its tributaries, including the Roundup area where record flows were observed. The Musselshell River at the gauge at Roundup crested at a record of 14.78 feet on May 26th. As the water on the Musselshell rose quickly on the 26th, floodwaters quickly inundated the town of Roundup. Portions of Highways 12 and 87 were closed in and around Roundup with up to 8 feet of water covering the roads in spots. This completely cut off the town from surrounding areas for several days. Homes and businesses in Roundup were inundated by flood waters with water up to rooftop levels in some cases. 39 homes experienced major damage and were complete losses. Another 110 homes and businesses experienced at least minor flood damage. …
National Weather Service event narrative, NOAA Storm Events Database (search the full record, event 308867)
| Date | Record | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2026-06-22 | Heavy RainKlein, Musselshell County | 0 | 0 | – | |
| 2026-05-13 | High WindMusselshell County · forecast zone Musselshell | 53 kt wind | 0 | 0 | – |
| 2026-03-12 | Winter StormMusselshell County · forecast zone Musselshell | 0 | 0 | – | |
| 2026-03-12 | High WindMusselshell County · forecast zone Musselshell | 55 kt wind | 0 | 0 | – |
| 2026-03-07 | High WindMusselshell County · forecast zone Musselshell | 52 kt wind | 0 | 0 | – |
| 2026-02-26 | High WindMusselshell County · forecast zone Musselshell | 53 kt wind | 0 | 0 | – |
| 2025-07-28 | Heavy RainRoundup, Musselshell County | 0 | 0 | – | |
| 2025-07-28 | HailRoundup Airport, Musselshell County | 1.25 in hail | 0 | 0 | – |
| 2025-07-28 | HailRoundup Airport, Musselshell County | 1.75 in hail | 0 | 0 | – |
| 2025-07-28 | HailRoundup, Musselshell County | 1.00 in hail | 0 | 0 | – |
| 2025-07-28 | FloodRoundup, Musselshell County | 0 | 0 | – | |
| 2025-06-15 | HailRoundup Airport, Musselshell County | 1.00 in hail | 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 |
|---|---|---|---|---|---|
| 2011-05-23 | FloodRoundup Airport, Musselshell County | 0 | 0 | $7.9M | |
| 1998-07-03 | Flash FloodRoundup, Musselshell County | 0 | 0 | $362K | |
| 1999-05-20 | TornadoRoundup, Musselshell County | F0 0.2 mi x 30 yd | 0 | 0 | $44K |
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 $3K, in the dollars of the day) holds: May 4, 1986 (tornado, Musselshell 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 Musselshell 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 | 3 | 2 | 0 | 0 | 20 | 110 | 65 | 30 |
| Winter storms | – | – | – | – | 5 | 41 | 30 | 11 |
| High wind and dust storms | – | – | – | – | 2 | 15 | 28 | 29 |
| Severe thunderstorm wind | 0 | 0 | 0 | 3 | 5 | 17 | 17 | 3 |
| Floods | – | – | – | – | 3 | 6 | 22 | 4 |
Source: NOAA NCEI Storm Events Database, records per calendar decade; zone records from the CZ_TYPE field (Z).
What time of year?
78% of its hail reports since 1955 fell in June and July. The two busiest months are in violet.
The values, month by month
Jan 22 · Feb 27 · Mar 32 · Apr 17 · May 53 · Jun 127 · Jul 119 · Aug 30 · Sep 8 · Oct 18 · Nov 14 · Dec 27 (records).
Source: NOAA NCEI Storm Events Database, records by the month they began.
Federal disaster declarations for Musselshell County
FEMA's register lists 15 declarations that include Musselshell County: 9 major disasters, 3 emergencies and 3 fire management assistance declarations. Most were for flood (4) and fire (4).
| Declared | Number | Type | Title |
|---|---|---|---|
| 2023-10-11 | DR-4745 | Flood | Flooding |
| 2020-09-02 | FM-5344 | Fire | Bobcat Fire |
| 2020-03-31 | DR-4508 | Biological | Covid-19 Pandemic |
| 2020-03-13 | EM-3476 | Biological | Covid-19 |
| 2018-10-31 | DR-4405 | Flood | Flooding |
| 2014-10-09 | DR-4198 | Severe Storm | Severe Storms, Straight-Line Winds, and Flooding |
| 2014-04-17 | DR-4172 | Flood | Ice Jams and Flooding |
| 2013-07-10 | DR-4127 | Flood | Flooding |
| 2012-06-26 | FM-2988 | Fire | Dahl Fire |
| 2011-06-17 | DR-1996 | Severe Storm | Severe Storms and Flooding |
| 2005-09-13 | EM-3253 | Hurricane | Hurricane Katrina Evacuation |
| 2000-08-30 | DR-1340 | Fire | Wildfires |
| 1999-07-26 | FM-2266 | Fire | Fishel Creek Fire Complex |
| 1997-07-25 | DR-1183 | Severe Storm | Severe Storms,Ice Jams, Snow Melt, Flooding |
| 1977-08-22 | EM-3050 | Drought | Drought |
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 Musselshell County had?
NOAA's Storm Events Database holds 35 flood or flash flood records for Musselshell County from 1997 to 2025, on 26 days, with 0 deaths. By flood insurance claims since 1978 (OpenFEMA, as of September 8, 2026), Musselshell County ranks 1569th of 2,942 U.S. counties.
The National Flood Insurance Program has paid $1.2 million on 60 claims filed in Musselshell County; the most in one year was 28 in 2011. Claims count insured losses only: uninsured flood damage is not in this file.
The values, year by year
1978: 1 · 1979: 23 · 1991: 1 · 2003: 2 · 2011: 28 · 2014: 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 Musselshell County
FEMA's National Risk Index rates Musselshell County Very Low overall, with an expected annual loss of $4.9 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.
| Hazard | Risk rating | Expected annual loss | Modeled frequency |
|---|---|---|---|
| Wildfire | Relatively Moderate | $1.4M | once in about 268 years (modeled) |
| Lightning | Relatively Moderate | $426K | 31 a year (modeled) |
| Cold Wave | Relatively Moderate | $1.3M | 4 a year (modeled) |
| Winter Weather | Relatively Moderate | $77K | 17 a year (modeled) |
| Landslide | Relatively Low | $3K | about once a year (modeled) |
| Hail | Relatively Low | $112K | 2.1 a year (modeled) |
| Drought | Very Low | $9K | 70 modeled event-days a year |
| Earthquake | Very Low | $23K | once in about 1,511 years (modeled) |
Source: FEMA National Risk Index, county table, December 2025 release. FEMA's National Risk Index map.
Counties that share a border with Musselshell 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 Musselshell CountyThe hazard risk calculator: 18 hazards beside the county's record
- Download Musselshell County's FEMA declarations (CSV)15 rows: every declaration that named the county, for your own analysis