Jefferson County, Montana
County storm and disaster record · FIPS 30043 · population 12,032 · 1,657 sq mi
NOAA's Storm Events Database holds 312 records for Jefferson County, Montana from 1950 through June 30, 2026, on 256 days; the most frequent are winter storm records (140 records). 210 of them are forecast-zone records, which the National Weather Service files once per zone: a county covered by several zones receives each one, so a single storm can add several records on the same day. FEMA has issued 11 declarations naming the county since 1975, 9 of them for natural hazards; the latest for a natural hazard was “Ice Jams and Flooding” on April 17, 2014.
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
- 312on 256 days, 1950 to June 30, 2026
- Deaths recorded
- 02 injuries
- Damage, 2025 dollars
- $477Kas filed (scale steps before 1993)
- Tornadoes
- 1strongest unrated
- FEMA declarations
- 11latest 2020
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 Jefferson County most?
The most frequent records are winter storm records: 140 since 2000. 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 |
|---|---|---|---|---|---|---|---|
| Winter storms | 140 | 128 | 2000-2026 | 0 | 0 | – | 24 of 56 |
| Hail | 56 | 37 | 1959-2025 | 0 | 0 | – | 40 of 56 |
| High wind and dust storms | 42 | 38 | 2001-2026 | 0 | 0 | – | 42 of 56 |
| Severe thunderstorm wind | 29 | 24 | 1958-2025 | 0 | 0 | $199K | 45 of 56 |
| Extreme cold | 16 | 13 | 2013-2025 | 0 | 0 | – | 29 of 56 |
| Wildfires | 12 | 10 | 2000-2026 | 0 | 2 | – | 6 of 56 |
| Heavy rain | 8 | 5 | 2014-2022 | 0 | 0 | – | 15 of 56 |
| Floods | 7 | 6 | 1998-2025 | 0 | 0 | $278K | 45 of 56 |
| Landslides and avalanches | 1 | 1 | 2022-2022 | 0 | 0 | – | 23 of 56 |
| Tornadoes | 1 | 1 | 2023-2023 | 0 | 0 | – | 48 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 Jefferson County had?
NOAA records 1 tornado in Jefferson County from 2023 to 2023, 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 1 tornado whose track touched Jefferson County since 1950 (NOAA's county records number 1, the same count); along their whole tracks they killed 0 people.
Map of the strongest tornado tracks in Montana.
Every tornado record filed for Jefferson County (1)
| Date | Place | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2023-08-06 | Boulder Airport, Jefferson County | EFU 3.66 mi x 70 yd | 0 | 0 | – |
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 Jefferson County?
The most recent record with damage, injuries or deaths is the August 2, 2000 wildfire (2 injuries).
High Ore/Boulder Hill fire, 12604 acres burned, cause unknown.
National Weather Service event narrative, NOAA Storm Events Database (search the full record, event 5170946)
| Date | Record | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2026-04-07 | High WindJefferson County and Broadwater County · forecast zone Elkhorn And Boulder Mountains | 53 kt wind | 0 | 0 | – |
| 2026-03-18 | WildfireJefferson County and 2 more · forecast zone Missouri Headwaters | 0 | 0 | – | |
| 2026-03-12 | High WindJefferson County and 2 more · forecast zone Missouri Headwaters | 54 kt wind | 0 | 0 | – |
| 2026-03-12 | High WindJefferson County and Broadwater County · forecast zone Elkhorn And Boulder Mountains | 55 kt wind | 0 | 0 | – |
| 2026-03-11 | Heavy SnowJefferson County and Broadwater County · forecast zone Elkhorn And Boulder Mountains | 0 | 0 | – | |
| 2026-03-05 | Heavy SnowJefferson County and 2 more · forecast zone Missouri Headwaters | 0 | 0 | – | |
| 2026-02-26 | High WindJefferson County and 2 more · forecast zone Missouri Headwaters | 51 kt wind | 0 | 0 | – |
| 2026-01-07 | Winter WeatherJefferson County and Broadwater County · forecast zone Elkhorn And Boulder Mountains | 0 | 0 | – | |
| 2025-12-27 | Winter WeatherJefferson County and Broadwater County · forecast zone Elkhorn And Boulder Mountains | 0 | 0 | – | |
| 2025-12-17 | High WindJefferson County and 2 more · forecast zone Missouri Headwaters | 62 kt wind | 0 | 0 | – |
| 2025-12-17 | High WindJefferson County and Broadwater County · forecast zone Elkhorn And Boulder Mountains | 65 kt wind | 0 | 0 | – |
| 2025-12-05 | Winter WeatherJefferson County and Broadwater County · forecast zone Elkhorn And Boulder Mountains | 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 |
|---|---|---|---|---|---|
| 2000-08-02 | WildfireBoulder, Jefferson County High Ore/Boulder Hill fire, 12604 acres burned, cause unknown. | 0 | 2 | – |
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 Jefferson 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 |
|---|---|---|---|---|---|---|---|---|
| Winter storms | – | – | – | – | 0 | 42 | 54 | 44 |
| Hail | 1 | 2 | 3 | 0 | 3 | 14 | 29 | 4 |
| High wind and dust storms | – | – | – | – | 0 | 9 | 15 | 18 |
| Severe thunderstorm wind | 1 | 7 | 2 | 0 | 3 | 4 | 8 | 4 |
| Extreme cold | – | – | – | – | 0 | 0 | 3 | 13 |
| Wildfires | – | – | – | – | 0 | 2 | 1 | 9 |
Source: NOAA NCEI Storm Events Database, records per calendar decade; zone records from the CZ_TYPE field (Z).
What time of year?
Records by month in Jefferson County. The two busiest months are in violet.
The values, month by month
Jan 30 · Feb 35 · Mar 17 · Apr 27 · May 20 · Jun 27 · Jul 35 · Aug 26 · Sep 19 · Oct 27 · Nov 24 · Dec 25 (records).
Source: NOAA NCEI Storm Events Database, records by the month they began.
Federal disaster declarations for Jefferson County
FEMA's register lists 11 declarations that include Jefferson County: 7 major disasters, 2 emergencies and 2 fire management assistance declarations. Most were for flood (3) and fire (3).
| Declared | Number | Type | Title |
|---|---|---|---|
| 2020-03-31 | DR-4508 | Biological | Covid-19 Pandemic |
| 2020-03-13 | EM-3476 | Biological | Covid-19 |
| 2014-04-17 | DR-4172 | Flood | Ice Jams and Flooding |
| 2012-08-29 | FM-5008 | Fire | Nineteen Mile 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 |
| 2000-07-24 | FM-2314 | Fire | Mt - Central Zone 3b Fire Complex |
| 1996-02-23 | DR-1105 | Severe Storm | Severe Storms, Flooding, and Ice Jams |
| 1981-05-27 | DR-640 | Flood | Severe Storms & Flooding |
| 1975-06-28 | DR-472 | Flood | Rains, Showmelt, 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 Jefferson County had?
NOAA's Storm Events Database holds 7 flood or flash flood records for Jefferson County from 1998 to 2025, on 6 days, with 0 deaths. By flood insurance claims since 1978 (OpenFEMA, as of September 8, 2026), Jefferson County ranks 2590th of 2,942 U.S. counties.
The National Flood Insurance Program has paid $6,966 on 5 claims filed in Jefferson County; the most in one year was 4 in 2011. Claims count insured losses only: uninsured flood damage is not in this file.
The values, year by year
2008: 1 · 2011: 4; 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 Jefferson County
FEMA's National Risk Index rates Jefferson County Very Low overall, with an expected annual loss of $8.6 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.
| Hazard | Risk rating | Expected annual loss | Modeled frequency |
|---|---|---|---|
| Landslide | Relatively Moderate | $185K | 1.2 a year (modeled) |
| Wildfire | Relatively Moderate | $1.3M | once in about 683 years (modeled) |
| Winter Weather | Relatively Moderate | $213K | 34 a year (modeled) |
| Lightning | Relatively Moderate | $358K | 34 a year (modeled) |
| Earthquake | Relatively Low | $672K | once in about 58 years (modeled) |
| Cold Wave | Relatively Low | $1.8M | 4.2 a year (modeled) |
| Riverine Flooding | Very Low | $3.9M | once in about 6 years (modeled) |
| Drought | Very Low | $4K | 84 modeled event-days a year |
Source: FEMA National Risk Index, county table, December 2025 release. FEMA's National Risk Index map.
Counties that share a border with Jefferson 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
- Winter storms in MontanaThe state's winter storm records, 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 Jefferson CountyThe hazard risk calculator: 18 hazards beside the county's record
- Download Jefferson County's FEMA declarations (CSV)11 rows: every declaration that named the county, for your own analysis